Document:

<PAGE>

                                                                  Exhibit 10.40

                                   October 21, 1999

Frederick H. Phillips
7 Fox Run
Middleton, MA  01949

Dear Fred:

     I am pleased to offer you the position of Senior Vice President and Chief
Financial Officer of Prime Response, Inc. (the "Company"), reporting directly to
me.  In that role you will have responsibility for all control, treasury,
management information and administrative activities of the Company.

     Compensation for that position includes a base salary of $180,000 per year
and an annual incentive bonus of 35% of that base salary ($63,000).  You will be
eligible to earn one fourth of that incentive ($15,750), based upon achievement
of the Company's fourth quarter goals (revenue of over $8.5 million).

     In addition, you will receive a stock option grant to purchase 125,000
shares of the Company's stock at $5.00 per share.  Since the Company is now
considered to be legally in registration, pricing on stock options is to be
calculated at a 10% discount to the low end of the filing range.  The Company is
expected to file for a public listing during the week of November 1.  Final IPO
pricing has yet to be determined and trading pricing is unknown.  However, the
Company is prepared to price your stock options at $5.00 per share.

     These shares will be vested according to the Company stock option standards
over a four-year period of time.

     Furthermore, you will have the opportunity to participate in Prime Response
benefits which include 3 weeks of vacation annually, health and life insurance
and a 401K retirement plan, which includes Company contribution.

     In the event that your employment is terminated without cause, you will
receive a severance that includes the continuation of all base salary and
benefits programs for one year.  Should you be terminated without cause
resulting from a change of control, all stock options granted will be 100%
vested.

<PAGE>
Frederick H. Phillips
October 21, 1999
Page Two

     This offer and compensation plan is dependent on your execution of the
standard Prime Response Employment Agreement.  Also, your employment with Prime
Response is contingent on the successful completion of the Company's standard
employment practices, including background investigation.

     Your background, experience and achievements to date will be put to
invaluable use as we work together to build a world class company. I'm excited
by the opportunity to work with you toward that end as you continue to build
your career with Prime Response.

     It is anticipated that you will begin your employment with Prime Response
on Monday, October 25.  Among our first initiatives will be the recruitment of
an equally world class corporate controller.

                                   Sincerely,

                                   /s/ Peter J. Boni
                                   Peter J. Boni
                                   President and Chief Executive Officer

Accepted and agreed to:

/s/ Frederick H. Phillips
-------------------------
Frederick H. Phillips<PAGE>

                                                                  Exhibit 10.41

August 10, 1999

Mr. James P. Plantan
9511 Oxborough Curve
Bloomington, MN 55437

Dear Jim,

I am pleased to offer you the position of Vice President, Business Development,
reporting directly to me.  In that role, you will have revenue responsibility
while directing, developing and coordinating the company's global partnerships,
alliances and alternate channels of distribution, to include all web related and
services firms, systems integrators and other industry vendors.  Seeing to the
direction and training of the company's global direct sales organization to use
these resources to their fullest will also be in your charge.  In addition, as
my direct report, you will participate in all corporate management activities as
a member of the company's executive staff.

Compensation for the position includes a base salary of $125,000 per year and an
incentive bonus of 30% of that base salary ($37,500).  You will be eligible to
earn one half of that for the remainder of 1999 ($18,750), based upon the
achievement of company goals. $10,000 of that will be guaranteed for 1999.  Over
achievement of goals will result in additional earnings.

In addition, a stock option to purchase 35,000 shares of common stock at the
prevailing price per share (currently $3.00 per share) will be recommended for
approval and submitted to the board of directors' compensation committee upon
their next scheduled meeting.

As discussed, your office will be located at your home site.  In addition, Prime
Response will provide you with administrative support at any Prime Response
field office as well as the corporate office located in Cambridge, MA.

Furthermore, you will have the opportunity to participate in Prime Response
benefits, which includes 3 weeks of vacation annually.  Please note that due to
your start date, your vacation allotment for the balance of 1999 will be (1
week) of the annual benefit.

In the event your employment is terminated without cause, Prime Response will
pay you six months severance as well as continue your medical benefits for the
      six-month period.
-----

The offer letter and compensation plans are dependent upon your execution of the
standard Prime Response Inc. Employment Agreement.  Also, your employment with
Prime Response is contingent on the successful completion of the company's
standard employment practices, including background investigation.

<PAGE>

This offer shall supercede any other offer of employment on behalf of Prime
Response Inc., either verbal or written, and will expire on August 12, 1999.

Your background, experience and achievements to date will be put to invaluable
use as we work together to build a world class company.  I'm excited for the
opportunity to work with you to that end as you continue to build your career
with Prime Response.

Sincerely,

Peter J. Boni
President & CEO

Accepted:

/s/ James P. Plantan
--------------------
James P. Plantan

Date: 8/11/99
      -------<PAGE>

                                                                  Exhibit 10.42

                                    August 5, 1999

Mr. Brad Braddock
927 San Antonio Avenue
Alameda, CA 94501

Dear Brad:

     Confirming our discussions, I am pleased to offer you the position of Vice
President, Product Marketing, reporting directly to me.  Your compensation in
this new role is at a base salary of $125,000, effective August 1, plus an
incentive bonus of 30% of that base pay ($37,500).  Any special incentive bonus
that you were offered for your role as Director of Business Development will
remain in effect through December 31, 1999.

     In addition, at the next meeting of the Compensation Committee, a stock
option package of 22,500 shares will be submitted and recommended for approval.
This will allot you a grant total of 35,000 shares, to include those that you
already hold.

     Among your responsibilities as Vice President of Product marketing are the
following:

     .    Competitive analysis, positioning and strategy
     .    Vertical marketing and penetration strategy for old and new products
          and services alike
     .    Analyst relations
     .    White paper content, construction and distribution
     .    Pricing and discounts
     .    Sales tools, presentation and training aids
     .    Web marketing Liaison and coordination with others both inside and
          outside the company, regarding product-related issues to insure the
          company has maximized its market penetration opportunities
     .    Branding, market awareness, lead flow in coordination with and
          direction of the global marketing communications

Marketing Communication will be expected to deliver the company's advertising,
public relations and promotional events, to include trade shows, conferences,
seminars and "webinars," and partner events. In addition, it will develop
consistent customer and sales collateral and enhance/update the company web site
and customer/prospect database.  With a successful
<PAGE>

branding effort should come a cost effective and qualified lead flow, which will
lead to increased sales and market penetration.

    In addition, you will be expected to work closely with the Business
Development effort in support of expanding the company's partnerships and
alternate channels of distribution.

    Your background and experience, plus your performance to date have given you
a great deal of organizational support as you embark upon your new role. I am
excited for you to continue your achievements with Prime Response and am looking
forward to working with you to build a world class company.

                                    Sincerely,

                                    /s/ Peter J. Boni
                                    Peter J. Boni
                                    President and CEO

PJB:jc

Accepted by: /s/ Brad Braddock
             -----------------
             Brad Braddock

Dated:  8/10/99
        -------<PAGE>

                                                                   Exhibit 10.43

                           DENVER PLACE PLAZA TOWER

                              AGREEMENT OF LEASE
                                    BETWEEN
            DENVER-STELLAR ASSOCIATES LIMITED PARTNERSHIP, LANDLORD
                                      AND
                         PRIME RESPONSE, INC., TENANT
<PAGE>

                           DENVER PLACE PLAZA TOWER

                              AGREEMENT OF LEASE
                                    BETWEEN
            DENVER-STELLAR ASSOCIATES LIMITED PARTNERSHIP, LANDLORD
                         PRIME RESPONSE, INC., TENANT

                               TABLE OF CONTENTS
                               -----------------

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
<S>                                                                         <C>
1.   Term.................................................................     1
2.   Base Rent............................................................     1
3.   Completion of Improvements...........................................     2
4.   Additional Rent......................................................     2
     (a)  Definitions.....................................................     2
     (b)  Expense Adjustment..............................................     4
     (c)  Adjustment for Services Not Rendered............................     4
     (d)  Tax Adjustment..................................................     4
     (e)  Partial Year....................................................     5
     (f)  Disputes........................................................     5
     (g)  Place of Payment................................................     5
     (h)  Tenant Taxes....................................................     5
     (i)  Delay in Computation............................................     6
5.   Use of Premises......................................................     6
6.   Condition of Premises................................................     6
7.   Services.............................................................     7
     (a)  List of Services................................................     7
     (b)  Billing for Electricity.........................................     9
          (i)   Landlord's Payment for Normal Service.....................     9
          (ii)  Measured Usage............................................     9
          (iii) Estimated Usage...........................................     9
     (c)  Interruption of Services........................................     9
8.   Alterations..........................................................    10
9.   Liens................................................................    11
10.  Insurance and Waiver of Subrogation..................................    11
11.  Fire or Casualty.....................................................    12
12.  Waiver of Claims - Indemnification...................................    12
13.  Nonwaiver............................................................    13
14.  Condemnation.........................................................    14
15.  Assignment and Subletting............................................    14
16.  Holdover.............................................................    16
17.  Estoppel Certificate.................................................    17
18.  Subordination........................................................    17
19.  Certain Rights Reserved By Landlord..................................    18
20.  Rules and Regulations................................................    19
21.  Remedies.............................................................    19
22.  Expenses of Enforcement..............................................    21
23.  Covenant of Quiet Enjoyment..........................................    21
24.  Security Deposit.....................................................    22
25.  Real Estate Broker...................................................    22
26.  Miscellaneous........................................................    23
     (a)  Rights Cumulative...............................................    23
     (b)  Captions and Usage..............................................    23
     (c)  Binding Effect..................................................    23
     (d)  Lease Contains All Terms........................................    23
     (e)  Submission of Lease.............................................    23
     (f)  No Air Rights...................................................    23
     (g)  Modification of Lease...........................................    23
     (h)  Substitution of Other Premises..................................    23
     (i)  Transfer of Landlord's Interest.................................    24
</TABLE>
<PAGE>

<TABLE>
<S>                                                                          <C>
     (j)  Recording; Short Form Memo......................................   24
     (k)  Covenants and Conditions........................................   24
     (l)  Application of Payments.........................................   25
     (m)  Security Interest and Tenant's Deposit..........................   25
     (n)  Governing Law; Partial Invalidity...............................   25
     (o)  Hazardous Materials.............................................   25
27.  Telephone and Telecommunications Service.............................   26
28.  Notices..............................................................   28
29.  Time is of the Essence...............................................   28
</TABLE>

     Addendum
     Exhibit A - Plan
     Exhibit B - Rules and Regulations
     Exhibit C - Lease Term Agreement
     Exhibit D - Parking Agreement
     Exhibit E - Workletter

                                       ii
<PAGE>

                                 OFFICE LEASE
                                 ------------

                           DENVER PLACE PLAZA TOWER
                               DENVER, COLORADO

     AGREEMENT OF LEASE made as of the 20th day of January, 1998 (hereinafter
referred to as the "Lease") between DENVER-STELLAR ASSOCIATES LIMITED
PARTNERSHIP, a Delaware limited partnership (hereinafter referred to as
"Landlord") and PRIME RESPONSE, INC., a Delaware corporation whose present
address is 1065 East Hillsdale Boulevard, Suite 310, Foster City, California
94404 (hereinafter referred to as "Tenant").

                             W I T N E S S E T H:

     Landlord hereby leases to Tenant, and Tenant hereby accepts from Landlord,
the premises (hereinafter referred to as the "Premises") containing
approximately 8,264 square feet of rentable area and designated on the plan
attached hereto as Exhibit "A" and further described as Suite 500 in the
building known as Denver Place Plaza Tower (hereinafter referred to as the
"Building") located at 1099 18th Street, Denver, Colorado, 80202, subject to the
covenants, terms, provisions and conditions of this Lease.  The Building, the
land upon which it is situated, all surrounding improvements, any garage or
other related improvements and all common areas appurtenant to, associated with
or servicing the Building are hereinafter called the "Real Property" or the
"Property".

     In consideration thereof, Landlord and Tenant covenant and agree as
follows:

     1.   Term.  The term of this Lease (the "Term") shall commence on that date
(the "Commencement Date") which is the later of (i) June 1, 1998 (the "Scheduled
Commencement Date") and (ii) three (3) months from the date that portion of the
Premises consisting of approximately 6,437 square feet of rentable area and
depicted as Phase One (the "Phase One Premises") are Ready for Occupancy
(hereinafter defined) and, unless sooner terminated as provided herein, shall
end, absolutely and without the need for notice from either party to the other,
on November 30, 2003 (the "Termination Date") subject to extension pursuant to
the provision of Paragraph 30 below.

     2.   Base Rent.  Subject to adjustment as herein provided, the Base Rent to
be paid hereunder shall be as follows:

          (a)  June 1, 1998 through May 31, 2000 (months 1 through 24):

               Phase One Premises  $102,992.04 per annum/$8,582.67 per month
               Phase Two Premises  $29,232.00 per annum/$2,436.00 per month
               TOTAL               $132,224.04 per annum/$11,018.67 per month

          (b)  June 1, 2000 through May 31, 2001 (months 25 through 36):

               Phase One Premises  $109,428.36 per annum/$9,119.03 per month
               Phase Two Premises  $31,059.00 per annum/$2,588.25 per month
               TOTAL               $140,487.36 per annum/$11,707.28 per month

          (c)  June 1, 2001 through November 30, 2003 (months 37 through 66):

               Phase One Premises  $115,866.00 per annum/$9,655.50 per month
               Phase Two Premises  $32,886.00 per annum/$2,740.50 per month
               TOTAL               $148,752.00 per annum/$12,396.00 per month

which shall be paid in advance on or before the first day of each calendar month
during the Term, in equal monthly installments, provided, however, that Tenant
shall pay the first full monthly installment at the time of execution of this
Lease.  If the Term commences other than on the first day of a month
<PAGE>

or ends other than on the last day of a month, the Base Rent for such month
shall be prorated. The Base Rent for the portion of the month in which the Term
commences shall be paid on the first day of the first full month of the Term.

     3.   Completion of Improvements.  INTENTIONALLY DELETED.

     4.   Additional Rent.  In addition to paying the Base Rent specified in
Paragraph 2 hereof, Tenant shall pay as "additional rent", the amounts
determined as hereinafter set forth in this Paragraph 4.  The Base Rent and
additional rent are sometimes herein collectively referred to as the "rent".
All amounts due under this Lease as additional rent shall be payable in the
sarne manner and at the same place as the Base Rent.

          (a)  Definitions.  As used in this Paragraph 4, the terms:
               -----------

               i.  "Operating Expense Base Amount" shall mean $5.54 per rentable
          square foot per annum.

               ii. "Tax Base Amount" shall mean $1.11 per rentable square foot
          per annum.

               iii "Calendar Year" shall mean each calendar year in which any
          part of the Term falls, through and including the year in which the
          Term expires.

               iv. "Tenant's Proportionate Share" shall mean [A] 1.25% during
          that portion of the Term that the Premises consists only of the Phase
          One Premises being the percentage calculated by dividing 6,437 square
          feet (being the rentable area of the Phase One Premises) by 512,995
          square feet (being 95% of the rentable area of the office space in the
          Building) and [B] 1.611% during that portion of the Term that the
          Premises consists of the Phase One Premises and that portion of the
          Premises consisting of approximately 1,827 square feet of rentable
          area and depicted as the Phase Two Premises on Exhibit A hereto (the
                                                         ---------
          "Phase Two Premises") being the percentage calculated by dividing
          8,264 square feet (being the rentable area of the Premises including
          the Phase One Premises and Phase Two Premises) by 512,995 square feet.
          The rentable area of the Premises has been calculated according to a
          method pursuant to which a portion of the common areas has been deemed
          included in the Premises.

               v.  "Taxes" for any Calendar Year shall mean the Building's
          Proportionate Tax Share of all real estate taxes and assessments,
          special or otherwise, levied or assessed upon that parcel of land
          known as Lots 1 through 32 inclusive and adjacent vacated alley, block
          95, East Denver Subdivision (the "Land") and/or the building during
          such Calendar Year; provided, however, that if Landlord subdivides the
          Land so that the Building is located on its own tax lot (i.e., there
          are no other buildings on such tax lot), then (1) such separate tax
          lot shall be referred to as the "Building Tax Lot", and (2) for each
          year that the Building Tax Lot is taxed separately from the remainder
          of the Land, the term "Taxes" shall mean all real estate taxes and
          assessments, special or otherwise, levied or assessed upon the
          Building Tax Lot and/or the Building during such Calendar Year. For
          purposes of this subparagraph "Buildings Proportionate Tax Share" for
          any Calendar Year shall mean the fraction the numerator of which is
          equal to the assessed valuation for the Building only for such
          Calendar Year and the denominator of which is equal to the sum of the
          assessed valuations for all buildings and improvements on the Land
          (including the Building) for such Calendar Year. Should the State of
          Colorado, or any political subdivision thereof, or any other
          governmental authority, impose a tax, assessment, charge or fee, which
          Landlord shall be required to pay, wholly or partially in substitution
          of any of the above Taxes, all such taxes, assessments fees or
          charges shall be deemed to constitute Taxes hereunder but shall be
          computed as if the Real Property and any other shared use real
          property referred to in this subparagraph was the only real property
          of Landlord. "Taxes" shall also include all fees and costs, including

                                       2
<PAGE>

          reasonable attorneys' fees, appraisals and consultants' fees, incurred
          by Landlord in seeking to obtain a reduction of, or a limit on, any
          increase in any Taxes (regardless of whether any reduction or
          limitation is obtained). In the event that the Real Property shall be
          for any taxes or assessments assessed under the same assessment as
          other real property, the amount of such taxes or assessment to be
          included within Taxes shall be such portion thereof as Landlord fairly
          and equitably shall deem attributable thereto. Notwithstanding
          anything in this paragraph to the contrary, Taxes shall specifically
          exclude inheritance taxes, gift taxes, transfer taxes, franchise
          taxes, excise taxes, income taxes, and profit taxes.

               vi. "Operating Expenses" shall mean all expenses, costs and
          disbursements (other than Taxes) of every kind and nature paid or
          incurred by or on behalf of Landlord in connection with the ownership,
          management, operation, maintenance and repair of the Property (and, as
          allocated by Landlord, those paid or incurred in connection with the
          ownership, operation, maintenance, management and repair of any garage
          or other improvements the use of which is shared by the Building and
          one or more other buildings) except the following:

                    [A]  Costs of alterations of any tenant's premises;

                    [B]  Principal or interest payments on loans secured by
               mortgages or trust deeds on the Real Property;

                    [C]  Costs of capital improvements, except that Operating
               Expenses shall include the costs as amortized over such number of
               years as Landlord may reasonably determine, with interest at the
               rate of 12% per annum on the unamortized amount, of any capital
               improvements which, (1) in Landlord's reasonable opinion, will
               have the effect of reducing any component cost included within
               Operating Expenses, (2) are made or installed to assure
               compliance with all governmental rules and regulations applicable
               from time to time, or (3) under generally applied real estate
               accounting practices may be expensed or treated as deferred
               expenses (and the amortization and interest so determined for
               each Calendar Year shall be included in Operating Expenses for
               that Calendar Year);

                    [D]  Leasing commissions for space in the Building;

                    [E]  Advertising and promotional expenses except the
               reasonable costs incurred (x) for distributing a newsletter to
               tenants and occupants of the Complex (as hereinafter defined),
               (y) for one (1) holiday party per calendar year that is held for
               all of the tenants and occupants of the Complex and (z) for one
               (1) health fair per calendar year that is held for all tenants
               and occupants of the Complex;

                    [F]  Expenses for correcting structural defects except that
               condition resulting from ordinary wear and tear shall not be
               deemed defects for purposes of this subparagraph;

                    [G]  Costs and expenses incurred by Landlord in the
                         enforcement of the terms of any other tenant lease;

                    [H]  Depreciation of the Building;

                    [I]  Costs for which Landlord receives reimbursement from
               others;

                    [J]  Any expense, other than property management fees,
               representing an amount paid to a related corporation, entity, or
               person which is in excess of the amount which would be paid in
               the absence of such relationship (provided, however, that Tenant
               acknowledges that Operating Expenses for

                                       3
<PAGE>

               any calendar year may include a management fee equal to five
               percent (5%) of the gross revenue collected during such calendar
               year for the Building and the Parking Garage (as hereinafter
               defined), even though such fee may exceed the management fee
               which would be incurred on a fair market basis if Landlord and
               the managing agent were not affiliated); and

                    [K]  Property management fees in excess of the greater of
               (y) five percent (5%) of the gross revenue collected during any
               calendar year for the Building and the Parking Garage and (z) the
               then prevailing fair market management fees payable in the
               central business district of Denver, Colorado for first class
               office buildings similar in age and quality to the Building
               ("Comparable Buildings") under management contracts similar to
               the then current management contract for the Building.

          (b)  Expense Adjustment.
               ------------------

               (i)   Tenant shall pay as additional rent for each Calendar Year,
          that amount ("Expense Adjustment Amount") which is Tenant's
          Proportionate Share of the amount by which the Operating Expenses
          incurred with respect to such Calendar Year exceed the Operating
          Expense Base Amount; provided, however, that in determining the amount
          of Operating Expenses for each Calendar Year, if less than 95% of the
          rentable office area of the Building shall have been occupied at any
          time during such Calendar Year, Operating Expenses shall be deemed for
          such Calendar Year to be in the amount reasonably determined by
          Landlord to be equal to that amount of like expenses which normally
          would be expected to be incurred had such occupancy been 95%
          throughout such Calendar Year.

               (ii)  The Expense Adjustment Amount with respect to each Calendar
          Year shall be paid in monthly installments, in advance on the first
          day of each calendar month during the course of such year, in amounts
          estimated from time to time by Landlord and communicated by written
          notice to Tenant. Landlord shall cause to be kept books and records
          showing Operating Expenses in accordance with generally accepted
          accounting principles. Following the close of each Calendar Year,
          Landlord shall cause the amount of the Expense Adjustment Amount for
          such Calendar Year to be computed based on Operating Expenses for such
          Calendar Year, and Landlord shall deliver to Tenant a statement of
          such amount; thereupon Tenant shall pay any deficiency as shown by
          such statement to Landlord within 30 days after receipt of such
          statement. If the total of the estimated monthly installments paid by
          Tenant during any Calendar Year exceed the actual Expense Adjustment
          Amount due from Tenant for such Calendar Year, then, at Landlord's
          option, such excess shall be either credited against payments next due
          hereunder or refunded by Landlord, provided Tenant is not then in
          default hereunder.

          (c)  Adjustment for Services Not Rendered.  If Landlord shall not be
               ------------------------------------
furnishing any particular work or service (the cost of which, if furnished by
Landlord would be included in Operating Expenses) to a tenant who undertakes to
itself perform or obtain such work or service in lieu of the furnishing thereof
by Landlord, Operating Expenses shall be deemed for purposes of this Paragraph 4
to be increased by an amount equal to the additional Operating Expenses, as
reasonably determined by Landlord, which would have been incurred during such
period if Landlord had at its own expense furnished such work or service to such
tenant.

          (d)  Tax Adjustment.  Tenant shall pay as additional rent for each
               --------------
Calendar Year that amount (the "Tax Adjustment Amount") which is Tenant's
Proportionate Share of the amount by which the Taxes incurred with respect to
such Calendar Year exceed the Tax Base Amount.  The Tax Adjustment Amount with
respect to each Calendar Year shall be paid in monthly installments, in an
amount estimated from time to time by Landlord and communicated by written
notice to Tenant.  Following the close of each Calendar Year, Landlord shall
cause the amount of the Tax Adjustment Amount for such Calendar Year to be
computed based on Taxes for such Calendar Year and Landlord shall deliver to
Tenant a

                                       4
<PAGE>

statement of such amount and Tenant shall pay any deficiency as shown by such
statement to Landlord within 30 days after receipt of such statement. If the
total of the estimated monthly installments paid by Tenant during any Calendar
Year exceeds the actual Tax Adjustment Amount due from Tenant for such Calendar
Year, then, at Landlord's option such excess shall be either credited against
payments next due hereunder or refunded by Landlord, provided Tenant is not then
in default hereunder. The amount of any refund of Taxes received by Landlord
shall be credited against Taxes for the year in which such refund is received.
In determining the amount of Taxes for any year, the amount of special
assessments to be included shall be limited to the amount of the installment
(plus any interest payable thereon) of such special assessment required to be
paid during such year as if the Landlord had elected to have such special
assessment paid over the maximum period of time permitted by law; if the
authority to whom such assessment is to be paid shall not permit such assessment
to be paid in installments, the amount of such assessment shall be treated as
being amortized over such number of calendar years, beginning with the Calendar
Year in which the assessment is payable, as Landlord shall reasonably determine,
with interest at the rate of 15% per annum on the unamortized amount, and such
amortization and interest for each Calendar Year shall be included in Taxes for
that Calendar Year.

          (e)  Partial Year.  If only part of any Calendar Year shall fall
               ------------
within the Term, the amounts computed as additional rent, with respect to such
Calendar Year under the foregoing provisions of this Paragraph 4 shall be
prorated in proportion to the portion of such Calendar Year falling within the
Term, but the expiration or termination of this Lease prior to the end of such
Calendar Year shall not impair the Tenant's obligation hereunder to pay such
prorated portion of such additional rent with respect to that portion of such
year falling within the Term.

          (f)  Disputes.  Any statement furnished to Tenant by Landlord under
               --------
the provisions of this Paragraph 4 shall constitute a final determination as
between Landlord and Tenant as to the rent set forth therein due from Tenant for
the period represented thereby, unless Tenant, within 60 days after such
statement is furnished, shall give a notice to Landlord that it disputes the
correctness thereof, specifying in detail the basis for such assertion. Pending
resolution of such dispute, Tenant shall pay all disputed amounts in accordance
with the statement furnished by Landlord. Landlord agrees, upon prior written
request during normal business hours to make available for Tenant's inspection
and audit, at Landlord's offices, Landlord's books and records which are
relevant to any items in dispute, provided Tenant has paid all amounts billed
to Tenant on account of the Expense Adjustment Amount and the Tax Adjustment
Amount and all installments thereof and all other rents and sums then and
previously due under this Lease. If the audit of such records shows that as to
such operating period, Landlord has overstated the amount of the Expense
Adjustment Amount or Tax Adjustment Amount payable by Tenant, Landlord shall
promptly credit to Tenant the amount of such overpayment(s). If Tenant's audit
of the books and records shows that Landlord overstated the actual Operating
Expenses and Taxes by an amount equal to 3% or more, then Landlord shall
reimburse Tenant for all reasonable out-of-pocket costs incurred by Tenant in
conducting the audit.

          (g)  Place of Payment.  Tenant shall, without any demand therefore and
               ----------------
without set-off, pay to DENVER-STELLAR ASSOCIATES LTD. PARTNERSHIP, A/R
DEPARTMENT, DENVER, COLORADO 80256-0170, or to such other person and/or at such
other place as Landlord may from time to time direct by notice given to Tenant,
the Base Rent as well as all other sums which may become due by Tenant under
this Lease.  All such other sums shall be payable as additional rent.

          (h)  Tenant Taxes.
               ------------

               (i)  Any provision hereof to the contrary notwithstanding, Tenant
          shall, upon demand from time to time, as additional rent, pay to Agent
          or, as Landlord may direct, to Landlord or to the tax collecting
          authority, the full amount of all taxes, levies, charges and
          assessments legally required or authorized to be collected by Landlord
          from Tenant or any subtenant or occupant of the Premises and all
          taxes,

                                       5
<PAGE>

          levies, charges and assessments required to be paid by Landlord
          (or imposed upon the Property) if not paid by or collected from Tenant
          or a subtenant or occupant of the Premises. Tenant hereby agrees to
          defend, indemnify and hold harmless Landlord from and against all
          loss, cost, liability and expenses (including counsel fees and costs
          of litigation) which Landlord may suffer, incur or be exposed to as a
          result of any assertion against Landlord of liability for any of the
          taxes referred to in this subparagraph (h), and from and against any
          penalties or interest relating thereto, which Tenant fails to pay
          pursuant hereto.

               (ii)  Tenant shall timely pay when due all taxes, levies, charges
          and assessments which are required to be paid by Tenant with respect
          to Tenant's use or occupancy of the Premises or which are or could
          become a lien upon the personal property, trade fixtures, furniture or
          facilities of Tenant on the Premises. Tenant hereby agrees to defend,
          indemnify and hold harmless Landlord from and against all loss, cost,
          liability and expense (including, without limitation, counsel fees and
          costs of litigation) which Landlord may suffer or incur, or to which
          Landlord may be exposed, as a result of Tenant's failure to pay any of
          the foregoing.

               (iii) Within 15 days after Tenant's receipt of written request
          from Landlord or an authorized taxing entity having jurisdiction,
          Tenant shall deliver to Landlord official receipts for the payment of
          all taxes due with respect to the personal property, trade fixtures,
          furniture or facilities of Tenant on the Premises. In addition, within
          15 days after written notice from Landlord to do so, Tenant shall
          deliver to Landlord official receipts for the payment of all other
          taxes, levies, charges and assessments within the scope of
          subparagraph (ii) above that were due and payable in the calendar year
          in which such notice is given and in the preceding calendar year. If
          Tenant shall fail to present any of the receipts referred to in this
          subparagraph within the times set forth herein, Landlord shall have
          the right to pay the amounts of the taxes which Landlord reasonably
          determines would have been covered thereby, together with the full
          interest and penalties chargeable thereon in accordance with law, and
          Landlord shall, upon demand, be entitled to reimbursement for all of
          such payments together with interest at the "Lease Interest Rate"
          (defined in Paragraph 21 hereof).

               (iv) Tenant shall cause all of the personal property, trade
          fixtures, furniture and facilities of Tenant on the Premises, and all
          alterations, additions and improvements made by Tenant to the Premises
          which for purposes of personal property taxes are treated as personal
          property (such as built-in cabinets, counters and partitions) to be
          assessed separately from Landlord's property, and, if they are not so
          separately assessed, Landlord shall be entitled to reimbursement,
          within 10 days after demand made from time to time, for any tax
          payable by Landlord which is attributable to any of such items taxable
          as personal property.

          (i)  Delay in Computation.  Delay in computation of the Expense
               --------------------
     Adjustment Amount or Tax Adjustment Amount shall not be deemed a default
     hereunder or a waiver of Landlord's right to collect any of such amounts.

     5.   Use of Premises.  Tenant shall use and occupy the Premises solely as a
general business office for the purpose of developing computer software
(including, but not limited to research, development and training) and any other
legally permitted uses related thereto and for no other purpose.

     6.   Condition of Premises.  The Tenant's taking possession of the Premises
or any portion thereof shall be conclusive evidence that the Premises or any
such portion was in good order and satisfactory condition when the Tenant took
possession.  At the expiration or other termination of this Lease or of Tenant's
right of possession, Tenant shall leave the Premises, and during the Term will
keep the same, in good order and condition, ordinary wear and tear, damage by
fire or other casualty (which fire or other casualty has not occurred through
the negligence of Tenant or those claiming under Tenant or their employees or
invitees respectively) alone excepted; and for that purpose, Tenant shall make
all necessary repairs and replacements.  Tenant shall give Landlord

                                       6
<PAGE>

prompt notice of any damage to or accident upon the Premises and of any breakage
or defects in the window glass, wiring or plumbing, heating, ventilating or
cooling or electrical apparatus or systems on or serving the Premises. Tenant
shall at the expiration or termination of this Lease or of Tenant's right of
possession, also have had removed from the Premises all furniture, trade
fixtures, office equipment and all other items of Tenant's property (including,
without limitation, the items Tenant is required to remove pursuant to Paragraph
8(b) hereof) so that Landlord may again have and repossess the Premises. All
such items not removed from the Premises at such expiration or termination,
shall conclusively be deemed to have been abandoned and may be appropriated,
sold, stored, destroyed or otherwise disposed of by Landlord without notice to
Tenant or any other party with an interest in such property and without any
obligation to account therefore. Tenant shall pay Landlord all expenses incurred
in connection with the disposition of such property, and if Landlord shall
choose to store any such items, Landlord shall have no liability for the
safekeeping thereof and such items may not be retrieved by Tenant or any other
person except upon payment of such charges as may be imposed for the removal and
storage. Tenant shall comply with all laws, rules, orders, ordinances and
regulations at any time issued or in force by any lawful authority, applicable
to Tenant or any other occupant of the Premises, or to the Premises, or to the
use or occupancy of the Premises; provided, however, that Tenant shall not be
required to make structural changes to the Building. Tenant shall, upon demand,
pay to Landlord the amount of any damages suffered or incurred by Landlord as a
result of any injury to any part of the Property other than the Premises, done
by Tenant or any subtenant or any agent, employee, contractor or invitee of
Tenant, including, without limitation, damage done by the bringing or removal of
furniture and other property. Tenant shall forthwith repair all damage done to
the Premises by installation or removal of furniture and property by Tenant or
any subtenant or by any agent, employee, contractor or invitee of Tenant or of
any subtenant or, if Landlord shall so request, pay to Landlord the cost of such
repair. Tenant shall not do or commit, or suffer or permit to be done or
committed, any act or thing as a result of which any policy of insurance of any
kind on or in connection with the Property shall become void or suspended, or
any insurance risk on or in connection with the Building or any other portion of
the Property shall (in the opinion of the insurer or any insurance organization)
be rendered more hazardous or require payment of a greater premium; without
limitation of any other rights and remedies of Landlord, Tenant shall pay as
additional rent the amount of any increase of premiums for such insurance,
resulting from any breach of this provision. Tenant shall leave the Premises in
a reasonably tidy condition on all days upon which janitorial services are to be
provided by Landlord. Landlord shall, at Landlord's expense, replace any glass
broken in the Premises windows in the exterior walls of the Building, unless
such glass is broken by Tenant, its servants, employees, agents, invitees,
licensees or contractors, in which case Tenant shall, upon demand, pay the cost
of replacement by Landlord. Tenant shall replace and pay for any other glass
broken in or about the Premises.

     7.   Services.

          (a)  List of Services.  Landlord shall provide the following services
               ----------------
on all days during the Term, except Sundays and holidays, unless otherwise
stated:

               (i)  Heating, ventilation and air conditioning (collectively
          "HVAC"), as deemed appropriate by Landlord (which shall be comparable
          with that provided in the Comparable Buildings), from Monday through
          Friday within the period from 6:00 a.m. to 6:00 p.m. and on Saturday
          within the period from 8:00 a.m. to 1:00 p.m., holidays excepted.
          Landlord shall furnish HVAC service to the Premises at other times
          upon written request of Tenant (which, at Tenant's election, may be
          delivered to Landlord by facsimile transmission at (303) (312-394 1),
          or such other number that Landlord notifies Tenant of from time to
          time during the Term, made no later than 3:00 p.m. on the business day
          on which after hours HVAC service is required or 3:00 p.m. on the next
          preceding business day for after hours HVAC service required on any
          non-business day. Tenant, within ten days after its receive of each
          bill therefore, will pay for all HVAC service requested and furnished
          at other times, at rates to be established from time to time by
          Landlord. At the time of the execution of this Lease the Tenant
          acknowledges that the charge for such after hours services is $65.00
          per hour. Landlord shall not be responsible for the failure of the
          HVAC system to provide normal comfort if such failure results from
          occupancy of the Premises by more than an average of one person for
          each 200 square feet of floor area or if Tenant

                                       7
<PAGE>

          uses heat-producing equipment or equipment the electrical load of
          which, when combined with the load of all lighting fixtures, exceeds
          2.5 watts per square foot of floor area in any one room or area.
          Unless otherwise consented to by Landlord, window coverings shall be
          uniform in the Building and shall be closed when exterior office
          windows are exposed to the sun without regard to Tenant's specific use
          of the space or to the installation of any computers or data
          processing equipment. In addition, if the Premises are used in a
          manner exceeding the aforementioned occupancy and electric load
          criteria or if such window covering requirement shall not be observed
          or if heat-producing or controlled climate equipment is used, Tenant
          shall pay to Landlord, promptly upon billing, Landlord's additional
          costs of supplying air conditioning resulting from such causes, at
          such rates as Landlord shall establish therefore. If due to use of the
          Premises in a manner exceeding the aforementioned occupancy and
          electrical load criteria, or due to the arrangement of partitioning,
          or the use of heat-producing or controlled climate equipment, or the
          distribution system within the Premises, impairment of normal
          operation of the HVAC system in the Premises results, necessitating
          changes in HVAC distribution system within the Premises, such changes
          may be made by Landlord upon request by Tenant at Tenant's sole cost
          and expense, provided that they can be accommodated by Landlord's
          systems. Tenant agrees at all times to cooperate fully with Landlord
          and to abide by all the regulations and requirements which Landlord
          may prescribe for the proper functioning and protection of the HVAC
          system. After Landlord has balanced the air-conditioning system for
          Tenant, if Tenant installs partitions, equipment, or fixtures
          requiring re-balancing of the system, Landlord, at Tenant's request
          and at Tenant's expense (which shall be charged as additional rent
          payable upon demand) shall endeavor to do such re-balancing. Landlord
          shall not charge Tenant for the initial balancing of the HVAC system.

               (ii)  Subject to subparagraph 7(b) hereof, electrical energy for
          standard building lighting fixtures provided by Landlord and for the
          operation of desk-top office equipment, provided that (A) the
          connected electrical load of such equipment does not exceed an average
          of 1.5 watts per square foot of the Premises and (B) the electricity
          so furnished for equipment uses will be at a nominal 120 volts and no
          electrical circuit for the supply of such use need have a current
          capacity exceeding 20 amperes. If Tenant's requirements for
          electricity are in excess of those set forth in the preceding
          sentence, and if, in Landlord's sole judgment, Landlord's facilities
          are inadequate for such additional requirements and if electrical
          energy for such additional requirements is available to Landlord,
          Landlord upon written request and at the sole cost and expense of
          Tenant, will furnish and install, or, at Landlord's sole discretion,
          permit Tenant to furnish and install, such additional wires, risers,
          conduits, feeders and switchboards as reasonably may be required to
          supply such additional requirements of Tenant provided (1) that the
          same shall be permitted by applicable laws and insurance regulations,
          (2) that, in Landlord's sole judgment, the same are necessary and will
          not cause permanent damage or injury to the Building or the Premises
          or cause or create a dangerous or hazardous condition or entail
          excessive or unreasonable alterations or repairs or interfere with or
          disturb other tenants or occupants of the Building, (3) that, in
          Landlord's sole judgment, the same will not in any way diminish or
          adversely affect the electricity which Landlord deems should remain
          available for other tenants, and (4) that Tenant, at Tenant's expense,
          shall, concurrently with the making of such written request, execute
          and deliver to Landlord, Tenant's written undertaking, in form and
          substance satisfactory to Landlord, obligating Tenant to fully and
          promptly pay the entire cost and expense of so furnishing and
          installing any additional wires, risers, conduits, feeders and/or
          switchboards.

               (iii) Ordinary water from the regular Building outlets for
          drinking, lavatory and toilet purposes.

               (iv)  Janitorial services Monday through Friday in and about the
          Premises (except holidays). If any material use made of the Premises
          after 6:00 p.m. shall by

                                       8
<PAGE>

          reason of work force scheduling or security, overtime, union rules or
          otherwise cause any increase in Landlord's cost for providing
          janitorial services, Tenant shall, as additional rent, pay all bills
          for reimbursement of Landlord for such increase attributable to
          Tenant's use of the Premises, within ten days after Tenant's receipt
          of such bill. All janitorial services shall be performed solely at
          Landlord's direction without interference from Tenant.

               (v)  Automatic passenger elevator service at all times.

               (vi) Freight elevator services subject to reasonable scheduling
          by Landlord.

          (b)  Billing for Electricity.
               -----------------------

               i.    Landlord's Payment for Normal Service. Landlord shall
          provide electric service on a twenty-four (24) hour basis and pay for
          electric service as described in the first sentence of subparagraph
          7(a)(ii) during the period from 6:00 a.m. to 6:00 p.m. from Monday
          through Friday, and during the period from 8:00 a.m. to 1:00 p.m. on
          Saturday, holidays excepted. In the event that Landlord, in Landlord's
          sole discretion, determines that Tenant's use of electricity exceeds
          the service to be provided under the first sentence of subparagraph
          7(a)(ii) above or goes materially beyond the hours specified in this
          subparagraph 7(b)(i), Tenant shall pay, as additional rent, such
          amounts for such excess and/or other hours use as shall be required
          under subparagraph 7(b)(ii) and (iii) below.

               (ii)  Measured Usage. In the event that Tenant's use of the
          Premises includes the use of computers or other electrical equipment
          or fixtures causing, in Landlord's reasonable determination, Tenant's
          use of electric service to exceed the service to be provided under the
          first sentence of subparagraph 7(a)(ii) above, or if there shall be at
          the Premises any other hours (i.e. outside the hours specified in
          subparagraph 7(b)(i)) use of electricity which Landlord believes may
          be material, Landlord shall install in the Premises or elsewhere, if
          Landlord shall so elect, or, if Tenant shall so request and if
          feasible in Landlord's reasonable judgment, one or more meters or
          other devices to measure the electricity used by such computers or
          other equipment or fixtures and/or such other hours use; and Tenant
          shall pay Landlord for such electricity within ten days after
          submission of each bill by Landlord therefore, at such rates as shall
          be from time to time determined by Landlord, provided that the rates
          charged by Landlord shall not exceed Landlord's cost (including,
          without limitation, taxes, fuel adjustment charges, and other like
          charges regularly passed on to customers by public utility companies
          and transformer costs) of supplying such electricity as determined by
          Landlord using reasonable accounting methods; and the cost of
          obtaining and installing such meters or other devices shall be paid by
          Tenant to Landlord within ten days after submission of each bill by
          Landlord to Tenant therefore.

               (iii) Estimated Usage. For any other hours use of electricity
          determined by Landlord to be material, and for any use of electricity
          which is determined by Landlord to be in excess of the service to be
          provided under the first sentence of subparagraph 7(a)(ii) above, and
          which is not actually measured, Tenant shall pay to Landlord, in
          monthly installments at the times prescribed for the monthly
          installments of the Base Rent, amounts, as reasonably estimated by
          Landlord from time to time, which Tenant would be required to pay for
          such excess and/or other hours electrical service if the same were
          actually measured as provided in subparagraph (b)(ii) above.

          (c) Interruption of Services.  Tenant agrees that Landlord shall not
              ------------------------
be liable for damages (by abatement of rent or otherwise, except for abatement
of Base Rent specifically provided for under this Paragraph 7(c)) for failure to
furnish or delay in furnishing any service, or for any diminution in the quality
or quantity thereof, when such failure or delay or diminution is occasioned, in
whole or in part, by repairs, renewals, or improvements, by any strike, lockout
or other labor trouble, by inability to secure fuel, by governmental laws,

                                       9
<PAGE>

regulations or orders by Landlord's compliance, in whole or in part with any
government promulgated program (whether voluntary or mandatory), for
conservation of energy by any accident or casualty whatsoever, by act or default
of Tenant or other parties, or by any cause beyond Landlord's reasonable
control; and such failures or delays or diminution shall never be deemed to
constitute an eviction or disturbance of the Tenant's use and possession of the
Premises or relieve the Tenant from paying rent or performing any of its
obligations under this Lease. Landlord's obligation to furnish services shall
also be further conditioned upon the availability of adequate energy sources
from the public utility companies then servicing the downtown Denver area.
Notwithstanding the foregoing provisions of this Paragraph 7(c), Base Rent shall
be abated in the event of the disruption of services in accordance with the
following provisions: (i) in the case of interruption of electrical power to the
Premises resulting in a shutdown of Tenant's computers, antennas, telephones, or
other office equipment, if such interruption continues for seven consecutive
days and as a result Tenant is not using the Premises (or the affected portion),
then the Base Rent for the Premises (or, if only a portion of the Premises is
affected, prorated for such portion) shall be abated commencing on the first day
following the seventh continuous day of such disruption until the service in
question has been restored; (ii) in the case of the substantial failure of the
water supply to the restroom or substantial failure of the HVAC system to the
Premises or of any portion of the life safety system, and if such interruption
continues for seven consecutive days without Landlord having provided reasonable
substitute temporary services, and as a result Tenant is not using the Premises
(or portion affected) then Base Rent for the Premises (or, if only a portion of
the Premises is affected, for such portion) shall be abated commencing on the
first day following the seventh consecutive day of such disruption until the
service in question has been restored.

     8.   Alterations.

          (a) Tenant shall not, without the prior written consent of Landlord
(which consent shall not be unreasonably withheld, conditioned or delayed), make
any alterations, improvements or additions to the Premises; provided, however,
Tenant shall be permitted to replace carpeting and repaint walls within the
Premises on the condition that Tenant notifies Landlord in writing not less than
three (3) days prior to the commencement of such work and Tenant otherwise
complies with the provisions of this Paragraph 8. If Landlord consents to any
alterations, improvements or additions, it may impose such conditions with
respect thereto as Landlord reasonably deems appropriate, including, without
limitation, Landlord's approval of plans and specifications for the work (but
Tenant shall not be entitled to rely upon such approval as evidencing that the
plans and specifications are proper in any respect), use of Landlord's approved
contractors to perform the work, insurance against liabilities which may arise
out of such work, permits necessary for such work and as-built drawings upon
completion of such work and the furnishing to Landlord of such security as is
determined by Landlord to be appropriate for the proper completion of such work
and its completion free of mechanics', materialmen's and similar liens or claims
thereof. Landlord shall concurrently with the granting of a consent to Tenant
under this Paragraph 8(a) notify Tenant of whether or not such alterations,
improvements or additions are required to be removed by Tenant upon the
expiration of this Lease and in the absence of the delivery of such notification
it shall be presumed that Landlord has elected not to require the removal of
such alterations, improvements or additions upon the expiration of this Lease.
All work done by Tenant or its contractors shall be done in a first-class
workmanlike manner, using only good grades of materials and without disturbing
other tenants and shall comply with all insurance requirements and all
applicable laws or ordinances and rules and regulations of governmental
departments or agencies. Before proceeding with any such work, Tenant shall
reimburse Landlord for Landlord's costs of Landlord's architects' review of
Tenant's plans and specifications. Any work performed by or for Tenant shall be
performed by competent workmen whose labor union affiliations are compatible
with those of the workmen who may be employed in the Building by Landlord, its
contractors or subcontractors, and Landlord shall have the right, at its option,
to directly supervise the work, which supervision shall be for the protection of
Landlord's interest only.

                                       10
<PAGE>

          (b) All alterations, additions or improvements made by Tenant and all
     fixtures attached to the Premises (other than Tenant's trade fixtures)
     shall become the property of Landlord and remain at the Premises or, at
     Landlord's option (as shall be indicated to Tenant at the time of the
     installation of such alterations, improvements or fixtures), any or all of
     the foregoing shall be removed at the cost of Tenant before the expiration
     or sooner termination of this Lease and in such event Tenant shall repair
     all damage to the Premises caused by the installation and/or removal
     thereof. Tenant shall not permit or suffer any signs advertisements or
     notices to be displayed, inscribed upon or affixed on any part of the
     outside or inside of the Premises, or in the Building, except on the
     entrance doors of the Premises, and then only of such size, color and style
     as Landlord may approve.  Landlord shall have the right to remove
     unauthorized signs at Tenant's expense.

     9.   Liens.

          (a) Tenant shall not permit there to be filed against the Property or
     Landlord's interest therein or any part of either, and shall within ten
     days after Tenant has notice of the claim or lien, remove or have removed,
     any mechanics', or materialmen's or other lien, or claim thereof, filed by
     reason of work, labor, services or materials provided for or at the request
     of Tenant (other than work, labor, services or materials provided by the
     Landlord) or any subtenant or occupant or for any contractor or
     subcontractor employed by Tenant or any subtenant or occupant, and shall
     exonerate, protect, defend and hold free and harmless Landlord against and
     from any and all such claims or liens.  Without limitation of the
     foregoing, if any such claim or lien be filed, Landlord may, but shall not
     be obligated to, discharge it either by paying the amount claimed to be due
     in the claim or lien or by procuring the discharge of such lien or claim by
     deposit or by bonding proceedings.  Any amount so paid by Landlord and all
     costs and expenses, including, without limitation, reasonable attorney's
     fees, in connection therewith, together with interest thereon at the Lease
     Interest Rate (hereinafter defined) from the respective dates of Landlord's
     making of the payments and incurring of the costs and expenses, shall
     constitute additional rent payable by Tenant under this Lease and shall be
     paid by Tenant to Landlord on demand.

          (b) At least ten days before the commencement of any work ordered by
     Tenant on the Premises, Tenant shall notify Landlord of the proposed work
     and of the names and addresses of the persons supplying labor and materials
     for the proposed work so that Landlord may avail itself of the provisions
     of statutes such as C.R.S.  (S)38-22-105(2).  During any such work on the
     Premises, Landlord, or its representatives, shall have the right to go upon
     and inspect the Leased Premises at all reasonable times, and shall have the
     right to post and keep posted thereon notices such as those provided for by
     C.R.S.  (S)38-22-105(2) or to take any action that Landlord may deem
     advisable to protect Landlord's interest in the Premises.

     10.  Insurance and Waiver of Subrogation.

          (a) Tenant, at its sole cost, shall maintain with responsible
     insurance companies acceptable to Landlord and qualified to do business in
     Colorado, general comprehensive public liability insurance against claims
     for personal injury (including death) and property damage, arising from
     occurrences in, on and about the Premises, with coverage on an occurrence
     basis in all cases of not less than a combined single limit of
     $3,000,000.00 per occurrence.  Landlord shall be designated a named insured
     in the policies for such insurance, which shall contain endorsements
     providing that the naming of more than one insured shall not operate to
     limit or void the coverage of any named insured relating to claims by
     another named insured.

          (b) Tenant, at its sole cost, shall maintain with responsible
     insurance companies acceptable to Landlord and qualified to do business in
     Colorado, "All Risk" or equivalent insurance upon all personal property
     upon the Premises and all equipment, fixtures, additions, alterations and
     improvements and betterments installed by or for Tenant upon the Premises,
     including, without limitation, anything in the nature of a leasehold
     improvement, if an amount which is at least 80% of the full replacement
     cost thereof, which insurance shall name

                                       11
<PAGE>

     Landlord as a named insured and Landlord's mortgagees as mortgagees under
     a standard mortgagee clause. In the event of damage or destruction to any
     leasehold improvements, Tenant shall use the proceeds of such insurance to
     repair or restore such leasehold improvements. If this Lease shall be
     terminated pursuant to Paragraph 11(a) on account of damage by fire or
     other casualty to the Building or the Premises, Landlord shall be entitled
     to all of the insurance proceeds payable under the aforesaid insurance
     relating to the leasehold improvements and the Premises.

          (c) Tenant shall, prior to the commencement of the Term, and at least
     30 days prior to the expiration date of each policy, furnish to Landlord
     certificates evidencing the coverage required hereinabove in this Paragraph
     and the renewal thereof, which certificates shall state that such insurance
     coverage may not be materially changed or cancelled without at least ten
     days prior written notice to Landlord and Landlord's mortgagee.

          (d) Notwithstanding anything herein to the contrary, Landlord and
     Tenant each hereby release the other, its officers, directors, partners,
     agents and employees (and Tenant hereby also releases Agent, its partners,
     officers, directors, agents and employees), to the extent of the releasing
     party's coverage under its insurance policies, from any and all liability
     for any loss or damage which may be inflicted upon the property of such
     party, notwithstanding that such loss or damage shall have arisen out of
     the negligence of the other party, its partners, officers, directors,
     agents or employees; provided, however, that this release shall be
     effective only with respect to occurrences occurring during such time as
     the appropriate policy of insurance of the party so releasing shall contain
     a clause to the effect that such release shall not affect the said policy
     or the right of the insured to recover thereunder.

     11.  Fire or Casualty.

          (a) If the Premises or the Building (including machinery or equipment
     used in the operation of the Building) shall be damaged by fire or other
     casualty and if such damage does not render all or a substantial portion of
     the Premises or Building untenantable, then Landlord shall repair and
     restore the same with reasonable promptness, subject to reasonable delays
     for insurance adjustments and delays caused by matters beyond Landlord's
     reasonable control.  If any such damage renders all or a substantial
     portion of the Premises or Building untenantable, Landlord shall have the
     right to terminate this Lease (with appropriate prorations of rent being
     made for Tenant's possession subsequent to the date of such damage of those
     tenantable portions of the Premises) upon giving written notice to the
     Tenant at any time within 120 days after the date of such damage; and if
     such notice is given Landlord shall have no obligation to repair or
     restore.  Landlord shall have no liability to Tenant, and Tenant shall not
     be entitled to terminate this Lease by virtue of any delays in completion
     of such repairs and restoration.  Rent, however, shall abate on those
     portions of the Premise as are, from time to time, untenantable as a result
     of such damage.

          (b) Notwithstanding anything to the contrary herein set forth,
     Landlord shall have no duty pursuant to this Paragraph 11 to repair or
     restore any portion of any alterations, additions or improvements in the
     Premises or the decorations thereto except to the extent that such
     alterations, additions, improvements and decorations were provided by
     Landlord at the beginning of the Term.

          (c) Within 120 days after any casualty to the Premises or the
     Building, Landlord shall give written notice to Tenant of the determination
     by Landlord's architect of the reasonably estimated period for completion
     of repairs.  If it is estimated such repairs will take longer than 180 days
     and such damage has been to the Premises or to a portion of the Building
     which materially interferes with Tenant's access to or use of the Premises,
     Tenant shall have the right to terminate this Lease by written notice
     delivered to Landlord within 15 days following receipt of Landlord's
     notice.

     12.  Waiver of Claims - Indemnification.  To the extent not prohibited by
law, Landlord, Amerimar Realty Management Co.-Colorado (herein "Agent"), Agent
and their respective officers,

                                       12
<PAGE>

directors, partners, agents, servants and employees shall not be liable for, and
it and they are hereby released by Tenant from all liability for, any damage
either to person or property or resulting from the loss of use thereof or any
other loss, or any death, sustained by Tenant or by other persons claiming
through Tenant due to the Property or any part thereof or any appurtenances
thereof becoming out of repair, or due to the happening of any accident or event
in, on or about the Property or due to any act or neglect of any tenant or
occupant of the Building or of any other person. This provision shall apply
particularly, but not exclusively, to damage caused by gas, electricity, snow,
frost, steam, sewage, sewer gas or odors, fire, water or by the bursting or
leaking of pipes, faucets, sprinklers, plumbing fixtures and windows, and shall
apply without distinction as to the person (whether Landlord, Agent or other)
whose act or neglect was responsible for the damage and whether or not such act
or neglect occurred before, at or after the execution of this Lease, and whether
the damage was due to any of the causes specifically enumerated above or to some
other cause of an entirely different kind. Tenant further agrees that all
personal property of Tenant upon the Premises, or upon loading docks, receiving
and holding areas, or elsewhere in, on or about the Property, shall be at the
risk of Tenant only, and that neither Landlord nor Agent, nor their partners,
directors or officers, shall be liable for any loss or damage thereto or theft
thereof, except to the extent caused by the gross negligence or willful
misconduct of Landlord, Agent and/or their respective partners, directors,
officers or employees. Without limitation of any other provisions hereof, Tenant
agrees to defend, protect, indemnify and save harmless Landlord and Agent, and
their respective partners, officers, directors and employees, from and against
all liability to third parties arising out of the acts or omissions of Tenant
or any subtenant or the servants, agents, employees, contractors, suppliers,
workmen and invitees of Tenant or any subtenant.

     Except to the extent caused by the gross negligence or willful misconduct
of Landlord, Agent and/or their respective partners, directors, officers or
employees, Tenant agrees to indemnify and save harmless, and upon request,
defend, Landlord, Agent, and their respective partners, directors, officers and
employees (herein called "indemnitees") against and from any and all claims by
or oil behalf of any person, arising out of or related to:

          (a) Tenant's use or occupancy of the Premises or the conduct of its
     business, or any activity, work, or thing, permitted or Suffered by Tenant,
     in, on or about the Premises or the Property;

          (b) any occurrence in, on or about the Premises;

          (c) any breach or default on Tenant's part in the performance or
     observance of, or compliance with, any term, covenant or condition on
     Tenant's part to be performed pursuant to the terms of this Lease; or

          (d) any act or negligence of Tenant or any subtenant, or any of their
respective agents, contractors, servants, employees, invitees or licensees,
whether or not the fault or negligence of Landlord, or of any other indemnitee
or of the agents, contractors, servants, employees, invitees or licensees of
Landlord or any indemnitee, (whether or not occurring before or after the
execution of this Lease), contributed thereto or was the cause thereof, and from
and against all costs, counsel fees, expenses, penalties, fines and liabilities
which Landlord or any other indemnitee may suffer or incur in connection with
any such claim and any action or proceeding brought with respect thereto.  In
the event that any action or proceeding shall be brought by reason of any such
claim, against any party to be indemnified hereunder, Tenant covenants that
Tenant, upon notice from such party and at Tenant's expense, shall resist and
defend such action or proceeding by counsel reasonably satisfactory to such
party.

     13.  Nonwaiver.  No waiver of any provision of this Lease shall be implied
by any failure of Landlord to enforce any remedy on account of the violation for
such provision, even if such violation be continued or repeated subsequently,
and no express waiver shall affect any provision other than the one specified in
such waiver and that one only for the time and in the manner specifically
stated.  No receipt of moneys by Landlord or its agents from tenant after the
termination of this Lease shall in any way alter the length of the Term or of
Tenant's right of possession hereunder or after the giving of any notice shall
reinstate, continue or extend the Term or affect any notice given

                                       13
<PAGE>

Tenant prior to the receipt of such moneys, it being agreed that after the
service of notice or the commencement of a suit or after final judgment for
possession of the Premises, Landlord may receive and collect any rent due, and
the payment and acceptance of payment of rent shall not waive or affect said
notice, suit or judgment.

     14.  Condemnation. In the event that the whole event that the whole of the
Premises shall be lawfully condemned or taken for a public or quasi-public use,
this Lease shall terminate as of the date that possession is to be surrendered
to the condemnor or taking authority. In the event that there shall be a lawful
condemnation or taking for any public or quasi-public use of any part of the
Building, without there being condemned or taken all of the Premises, then, at
the option of Landlord, exercisable by notice given to Tenant not later than 90
days after the date upon which Landlord receives notice of the taking or
condemnation, this Lease shall terminate as of the date that possession of the
Premises taken is required to be surrendered to the condemnor or taking
authority. In the event of any such taking or condemnation of all or any part of
the Premises or of all or any part of the Property, Tenant shall have no claim
against Landlord and shall not have any claim or right to any portion of the
amount that may be awarded as damages or paid as a result of such taking or
condemnation; and all rights of Tenant to damages therefore are hereby assigned
by Tenant to Landlord and Tenant shall have no claim against Landlord or the
condemner for the value of the unexpired term of this Lease. However, the
foregoing provisions of this section shall not be construed to deprive Tenant of
the right to claim and receive payment from the condemner or taking authority
for moving and related expenses as long as such claim or the payment thereof
does not reduce the award which Landlord would otherwise be entitled to receive.
In the event of any such taking or condemnation of part of the Premises, the
Base Rent, the Tax Adjustment and the Operating Expense Adjustment shall be
proportionately reduced from the date that possession is required to be
surrendered to the condemnor or taking authority.

     15.  Assignment and Subletting.

          (a) Tenant shall not, without the prior written consent of Landlord
     (which shall not be unreasonably withheld, conditioned or delayed in the
     case of an assignment or subletting), (i) assign, convey or mortgage this
     Lease or any interest hereunder except to an Affiliate (hereinafter
     defined) who is not a Prohibited Entity (hereinafter defined); (ii) suffer
     to occur or permit to exist any assignment of this Lease to an entity which
     is not an Affiliate ("Non-Affiliate"), or any lien upon Tenant's interest
     hereunder, whether voluntarily, involuntarily or by operation of law; (iii)
     sublet the Premises or any part thereof to a Non-Affiliate, (iv) permit the
     use of the Premises by any parties other than Tenant, its Affiliates and
     their respective employees.  Any such action on the part of Tenant without
     Landlord's consent, shall be void and of no effect.  Landlord's consent to
     any assignment, subletting or transfer or any assignment, subletting or
     transfer permitted in this Paragraph 15, or Landlord's election to accept
     any assignee, subtenant or transferee as the tenant hereunder and to
     collect rent from such assignee, subtenant or transferee shall not release
     Tenant or any subsequent tenant from any covenant or obligation under this
     Lease.  Landlord's consent to any assignment, subletting or other act or
     occurrence requiring Landlord's consent shall not constitute a waiver of
     Landlord's right to withhold its consent to any future assignment,
     subletting or act or occurrence requiring Landlord's consent.  Without
     limitation of the circumstances in which Landlord's withholding of consent
     to an assignment or subletting shall not be unreasonable, it shall not be
     unreasonable for Landlord to withhold its consent if the reputation,
     financial responsibility, or business of the proposed assignee or subtenant
     is unsatisfactory to Landlord, or if Landlord deems such business to be not
     consonant with that of other tenants in the Building, or if the intended
     use by the proposed assignee or subtenant conflicts with any commitment
     made by landlord to any other tenant in the Building, or if in Landlord's
     reasonable judgment the assignment or subletting will have financial
     consequences adverse to Landlord's interest, or if the proposed assignee or
     subtenant is a Prohibited Entity.

          (b) At least forty-five (45) days prior to any proposed subletting or
     assignment to a Non-Affiliate, Tenant shall submit to Landlord a statement
     seeking Landlord's consent and containing the name and address of the
     proposed subtenant or assignee, the terms of the proposed sublease or
     assignment (including, without limitation, the date upon which the assignee
     or subtenant is the take possession) and such financial and other
     information with

                                       14
<PAGE>

     respect to the proposed assignee or subtenant as Landlord reasonably may
     request. Landlord shall indicate its consent or non-consent within six (6)
     business days of its receipt of said statement. Tenant shall notify
     Landlord in writing of any subletting or assignment to an Affiliate, Tenant
     shall submit to Landlord a statement containing the name, address and
     affiliation of the proposed subtenant or assignee to the Tenant, the terms
     of the proposed sublease or assignment and financial and other information
     with respect to the proposed assignee or subtenant as Landlord may
     reasonably request.

          (c) Contemporaneously with any request or proposal by tenant to sublet
     or assign any part of this Lease, Tenant shall pay all costs, including
     reasonable attorneys' fees, incurred by Landlord or anticipated to be
     incurred by Landlord, in connection with Landlord's investigation of any
     financial or other information of the proposed assignee or subtenant all of
     such costs will in no event exceed $750.  Landlord may require that all or
     a portion of the costs or anticipated costs be paid in advance by Tenant.
     The payment of such costs shall not obligate Landlord in any way to consent
     to any proposed assignment or subletting nor shall the amount of costs paid
     by Tenant be applied or used as a set-off to any amounts due or to become
     due by Tenant to Landlord.

          (d) In addition to withholding its consent, Landlord shall have the
     additional right, exercisable within such 30 day period, to terminate this
     Lease in its entirety (where Tenant seeks to assign this Lease or sublet
     the entire Premises to a Non-Affiliate) or as to that portion of the
     Premises which Tenant seeks to sublet (where Tenant seeks to sublet only a
     portion of the Premises to a Non-Affiliate for a term exceeding two (2)
     years at a time when the remaining Term of the Lease is three (3) years or
     more).  Landlord may exercise such right to terminate by giving written
     notice to Tenant at any time prior to Landlord's written consent to such
     assignment or sublease.  In the event that Landlord exercises such right to
     terminate, (i) the termination shall be effective as of such date as
     Landlord may specify in its notice which shall not be later than the later
     of [A] the proposed date for possession by such Non-Affiliate assignee or
     subtenant, or [B] ninety (90) days after the date of Landlord's notice of
     termination to Tenant and (ii) as of the effective date of such termination
     Tenant shall have no further liability under this Lease with respect to
     that portion of the Premises which is the subject of such termination:

          (e) If Landlord fails to exercise its termination right and its right
     to withhold its consent as set forth in the preceding subsections, Tenant
     shall pay to Landlord fifty percent (50%) of all profit derived by Tenant
     from the assignment or sublease ("Sublease Profit").  The Tenant shall not
     be required to pay any Sublease Profit derived by Tenant from an assignment
     or sublease with an Affiliate.  In determining Sublease Profit the Tenant
     shall only be permitted to deduct (i) leasing commissions and brokerage
     fees paid by Tenant and (ii) any other reasonable out-of-pocket costs paid
     by Tenant and which are directly attributable to such assignment or
     sublease.  Whenever requested by Landlord, Tenant shall furnish Landlord
     with a statement, certified by an authorized officer of Tenant as true,
     correct and complete, setting forth in detail the computation of profit
     (which computation shall be based upon generally accepted accounting
     principles), and Landlord, or its representatives, shall have access to the
     books, records and papers of Tenant in relation thereto, and to make copies
     thereof. Any rent in excess of that paid by Tenant hereunder realized by
     reason of such assignment or sublease less the costs described above shall
     be deemed all item of such profit.  Such percentage of Tenant's profits
     shall be paid to Landlord promptly by Tenant upon Tenant's receipt from
     time to time of periodic payments from such assignee or subtenant or at
     such other earlier time as Tenant shall realize its profits from such
     assignment or sublease.

          (f) Landlord and Tenant further agree that Tenant shall not publish or
     otherwise disseminate any written advertising material in connection with
     any proposed assignment or sublease of all or any portion for the Premises
     (the "Advertising") without Landlord's prior written approval for the same,
     which approval shall not unreasonably withheld; provided, however, that no
     Advertising shall contain any reference to the price to be charged in
     connection with any proposed assignment or sublease.

                                       15
<PAGE>

          (g) For the purposes of this Lease, the following terms shall have the
     following meanings:

               (i)   "Affiliate" shall mean [A] any person or entity which,
          directly or indirectly, controls Tenant or is controlled by Tenant or
          is under common control with Tenant, [B] any successor to Tenant by
          merger, consolidation or other operation of law, [C] any person or
          entity to whom all or substantially all of the assets of Tenant are
          conveyed or [D] any person or entity purchasing the business which
          Tenant conducts at the Premises.

               (ii)  "Prohibited Entity", unless otherwise agreed in writing by
          Landlord, shall mean [A] a governmental or a governmental subdivision,
          instrumentality or agency, [B] a school, college or university, [C] an
          employment, recruitment or temporary help service or agency, [D] a
          collection agency, [E] any entity or an affiliate thereof which has
          previously defaulted in the performance of its obligations under a
          lease concerning any portion of the Building or any building located
          within the Denver Place complex known and numbered as 999 - 18th
          Street, Denver, Colorado 80202 (collectively the "Complex"), or [F]
          any person, entity or affiliate of Landlord, is either currently
          negotiating or, within the six month period preceding Tenant's request
          for the assignment or sublease, with whom Landlord, or any affiliate
          of Landlord, has negotiated to lease space in the Complex. An
          insurance agency (other than Alexander & Alexander, Inc.) shall be
          deemed to be a Prohibited Entity if such insurance agency (x)
          subleases or occupies any floor of the Building leased to or occupied
          by Alexander & Alexander Inc., (y) subleases or occupies any portion
          of the 29th through 31st floors of the Building or (z) subleases or
          occupies more than 12,000 square feet of rentable area in the
          Building.

     16.  Holdover.  If the Tenant or any person claiming through the Tenant
shall retain possession of the Premises or any part thereof after the expiration
or earlier termination of the Term and if Landlord shall consent to such
continuation of possession, such possession shall be (unless the parties hereto
shall otherwise have agreed in writing) deemed to be under a month-to-month
tenancy which shall continue until either party shall notify the other in
writing, at least 30 days prior to the end of any calendar month, that the party
giving such notice elects to terminate such tenancy at the end of such calendar
month, in which event such tenancy shall so terminate. Anything contained in the
foregoing provisions of this paragraph to the contrary notwithstanding, the
rental payable with respect to each such monthly period shall be 150% of the
monthly Base Rent and 150% of the monthly Tax Adjustment Amount and of the
monthly Expense Adjustment Amount (both calculated in accordance with the
provisions of Paragraph 4 hereof) which would have been payable had this Lease
been renewed until the end of the calendar year which includes such month on the
terms and conditions in effect immediately prior to the expiration or
termination of the Term for the first three (3) months of Tenant's holdover and
150% of the monthly Base Rent and 200% of the monthly Tax Adjustment Amount and
of the monthly Expense Adjustment Amount (both calculated in accordance with the
provisions of Paragraph 4 hereof) which would have been payable had this Lease
been renewed until the end of the calendar year which includes each month on the
terms and conditions in effect immediately prior to the expiration or
termination of the Term for any period after the first three (3) months of
Tenant's holdover; and such month-to-month tenancy with Landlord's consent shall
be upon the same terms and subject to the same conditions as those which are set
forth in this Lease except as aforesaid.  If Tenant or any person claiming
through Tenant shall retain possession of the Premises or any part thereof,
after the expiration or earlier termination of the term or of Tenant's right of
possession, and if such retention shall be without Landlord's consent, Tenant
shall pay Landlord (a) for each month or portion thereof during which such
possession continues, an amount equal to the rental to be paid for each month
pursuant to the foregoing provisions of this Paragraph when such possession is
with Landlord's consent, plus all other sums which would have been payable
hereunder had the term continued during such retention of possession and (b) all
other damages sustained by Landlord, whether direct or consequential, by reason
of such retention of possession.  During any such retention of possession
without Landlord's consent, all of Tenant's obligations with respect to the use,
occupancy and maintenance of the Premises shall continue.  The provisions of
this paragraph shall not be deemed to limit or constitute a waiver of any other
rights or remedies of Landlord provided herein or at law or in equity and
applicable to unlawful retention of possession or otherwise.

                                       16
<PAGE>

     17.  Estoppel Certificate.  Tenant shall from time to time, within ten days
after Tenant's receipt of Landlord's written request therefore, execute,
acknowledge and deliver to Landlord a written instrument in recordable form (a)
certifying (i) that this Lease is in full force and effect and has not been
modified, supplemented or amended in any way (or, if there have been
modifications, supplements or amendments thereto, that it is in full force and
effect as modified, supplemented or amended, and stating such modifications,
supplements and amendments) and that this Lease (as modified, supplemented or
amended, as aforesaid) represents the entire agreement among Landlord and Tenant
as to the Premises and the leasehold, (ii) the dates to which the Base Rent,
additional rent and other charges arising hereunder have been paid, (iii) the
amount of any prepaid rents or credits due to Tenant, if any; and (iv) that if
applicable, Tenant has entered into occupancy of the Premises; and (b) stating,
to the best knowledge of Tenant, whether or not all conditions under the Lease
to be performed by Landlord prior to the date of such certificate have been
satisfied and whether or not Landlord is then in default in the performance of
any covenant, agreement or condition contained in this Lease and specifying, if
any, each such unsatisfied condition and each such default; and (c) stating any
other fact or certifying any other condition reasonably requested by Landlord or
by any mortgagee or prospective mortgagee or purchaser of the Property or of any
interest therein.

     18.  Subordination.

          (a) This Lease shall be subject and subordinate at all times to the
     lien of any mortgage or deed of trust, heretofore or hereafter placed by
     Landlord on the Property or any part thereof and of all renewals,
     modifications, consolidations, replacements and extensions thereof (all of
     which are hereinafter referred to collectively as a "mortgage"), all
     automatically and without the necessity of any further act on the part of
     Tenant to effectuate such subordination.  Tenant shall, at the request of
     the holder of any such mortgage, upon foreclosure thereof attorn to such
     holder.  Tenant shall also execute, acknowledge and deliver, within 15 days
     after Tenant's receipt of demand from Landlord or such holder, such other
     instrument or instruments evidencing such subordination of Tenant's right,
     title and interest under this Lease to the lien of any such mortgage, and
     such other instrument or instruments of attornment, as shall be desired by
     such holder.  Notwithstanding the foregoing provisions of this Paragraph
     18(a) as a condition precedent to Tenant's attornment and subordination to
     the lien of any mortgage or deed of trust hereafter placed by Landlord on
     the Property or any portion thereof, provided the Premises then consist of
     a rentable area of not less than 10,000 square feet, the holder of any such
     mortgage or deed of trust shall agree in writing not to disturb Tenant's
     rights under this Lease provided Tenant is not in default in the
     performance of its obligations hereunder.  In the event the Premises
     consist of a rentable area of less than 10,000 square feet at the time of a
     request for subordination to the lien of any mortgage or deed of trust
     hereafter placed by Landlord on the Property or any portion thereof,
     Landlord agrees to use reasonable efforts to obtain such holder's agreement
     not to disturb Tenant's rights under this Lease provided Tenant is not in
     default in the performance of its obligations hereunder on the condition
     that Tenant shall be solely responsible for all fees, costs and expenses
     charged by such holder(s) for the preparation and negotiation of the terms
     and conditions of the nondisturbance.

          (b) Anything contained in the foregoing provisions of this Paragraph
     to the contrary notwithstanding, any such holder may at any time
     subordinate its mortgage to this Lease, without the necessity of obtaining
     Tenant's consent, by giving notice of the same in writing to Tenant, and
     thereupon this Lease shall be deemed to be prior to such mortgage without
     regard to their respective dates or execution, delivery or recordation
     and/or the date of commencement of Tenant's possession, and in that event
     such holder shall have the same rights with respect to this Lease as though
     this Lease shall have been executed, delivered and recorded prior to the
     execution and delivery of such mortgage.

          (c) If Landlord is or becomes lessee of premises of which the Premises
     are a part, Tenant agrees that, automatically and without the necessity of
     any further act, Tenant's possession shall be as a subtenant and shall be
     subordinate to the interest of Landlord's lessor, its heirs, personal
     representatives, successors and assigns (which lessor, its heirs, personal
     representatives, successors and assigns, or any of them, is hereinafter
     called "Paramount Lessor"), but notwithstanding the foregoing, if
     Landlord's tenancy shall terminate by

                                       17
<PAGE>

     expiration, by forfeiture or otherwise, then Tenant hereby agrees, upon
     request of Paramount Lessor, to attorn to Paramount Lessor, and to
     recognize such lessor as Tenant's landlord for the balance of the term of
     this lease and any extensions or renewals hereof. Tenant shall execute,
     acknowledge and deliver, upon demand by Landlord or Paramount Lessor, such
     other instrument or instruments evidencing such subordination of Tenant's
     right, title and interest under this Lease to the interest of such lessor,
     and such other instrument or instruments of attornment, as shall be
     prescribed by such lessor.

     19.  Certain Rights Reserved By Landlord.  Landlord shall have the
following rights, each of which Landlord may exercise without notice to Tenant
and without liability to Tenant for damage or injury to property, person or
business on account of the exercise thereof, and the exercise of any such
rights shall not be deemed to constitute an eviction or disturbance of Tenant's
use or possession of the Premises and shall not give rise to any claim for set-
off or abatement of rent or any other claim:

          (a) to change the Building's name or street address;

          (b) to install, affix and maintain any and all signs on the exterior
     and on the interior of the Building;

          (c) to decorate or to make changes, repairs, alterations, additions,
     or improvements, whether structural or otherwise (including alterations in
     the configuration of, and elimination of, any common areas), in and about
     the Building and Property or any part thereof, and for such purposes to
     enter upon the Premises, and during the continuance of any of said work, to
     temporarily close doors, entry ways, public space and corridors in the
     Building and to interrupt or temporarily suspend services or use of
     facilities; but Landlord shall endeavor to perform any such work in or
     about the Premises so as to cause the minimum inconvenience to Tenant
     practicable under the circumstances;

          (d) to designate and approve all window coverings used in the
     Building;

          (e) to approve, disapprove or restrict the weight, size and location
     of safes, vaults and other heavy equipment and articles in and about the
     Premises and the Building so as not to exceed the live load per square foot
     designated by the structural engineers for the Building, and to require all
     such items and furniture and similar items to be moved into or out of the
     Building and Premises only at such times and in such manner as Landlord
     shall direct in writing.  Tenant shall not install or operate machinery or
     any mechanical devices of a nature not directly related to Tenant's
     ordinary use of the Premises without the prior written consent of Landlord.
     Tenant's movements of property into or out of the Building or Premises and
     within the Building are entirely at the risk and responsibility of Tenant,
     and Landlord reserves the right to require permits before allowing any
     property to be moved into or out of the Building or Premises;

          (f) to establish controls for the purpose of regulating all property
     and packages, both personal and otherwise, to be moved into or out of the
     Building and Premises and all persons using the Building after normal
     office hours;

          (g) to regulate delivery and service of supplies in order to insure
     the cleanliness and security of the Premises and to avoid congestion of the
     loading docks, receiving areas and freight elevators;

          (h) to show the Premises to prospective tenants at reasonable hours
     upon reasonable prior oral notice to Tenant during the last twelve months
     of the Term and, if vacated or abandoned, to show the Premises at any time
     and to prepare the Premises for re-occupancy;

          (i) to erect, use and maintain pipes, ducts, wiring and conduits, and
     appurtenances thereto, in and through the Premises at reasonable locations,
     provided Landlord takes

                                       18
<PAGE>

     reasonable efforts to minimize the interference with Tenant's use and
     enjoyment of the Premises; and

          (j) to enter the Premises at any reasonable time upon reasonable
     prior oral notice (except in an emergency when no notice shall be required)
     to inspect the Premises.

     20.  Rules and Regulations.  Tenant shall, and shall cause all of its
subtenants and occupants, its and their agents, employees, invitees and
licensees to, observe faithfully, and comply strictly with, the rules and
regulations attached to this Lease as Exhibit "B", as they may be supplemented
and revised by Landlord from time to time, and such other rules and regulations
promulgated from time to time by Landlord, as in the Landlord's judgment may be
desirable for the safety, care and cleanliness of the Building and the Premises,
or for the preservation of good order therein.  Landlord shall not be liable to
Tenant for violation of such rules and regulations by, or for Landlord's failure
to enforce the same against, any other tenant, its subtenants and occupants and
its and their agents, employees, invitees or licensees, nor shall any such
violation or failure constitute, or be treated as contributing to, an eviction,
actual or constructive, or affect Tenant's covenants and obligations hereunder,
or allow Tenant to reduce, abate or offset the payment of any rent under this
Lease.

     21.  Remedies.

          (a) If default shall be made in the payment of any rent or any
     installment thereof or in the payment of any other sum required to be paid
     by Tenant under this Lease or under the terms of any other agreement
     between Landlord and Tenant and such default shall continue for ten days,
     or if default shall be made in the observance or performance of any of the
     other agreements, covenants or conditions in this Lease (or in any other
     agreement between Landlord and Tenant) which Tenant is required to observe
     and perform and such default shall continue for fifteen (15) days after
     written notice to Tenant unless such default is not reasonably capable of
     being cured within such fifteen (15) day period, in which event there shall
     be a default if Tenant fails to commence such cure within fifteen (15) days
     or thereafter fails to diligently pursue such cure to completion which
     shall in no event exceed sixty (60) days, or if the interest of Tenant in
     this Lease shall be levied on under execution or other legal process, or

          (b) if Tenant becomes the subject of commencement of an involuntary
     case under the federal bankruptcy law as now or hereafter constituted, or
     there is filed a petition against Tenant seeking reorganization,
     arrangement, adjustment or composition of or in respect of Tenant under the
     federal bankruptcy law as now or hereafter constituted, or under any other
     applicable federal or state bankruptcy, insolvency, reorganization or other
     similar law, or seeking the appointment of a receiver, liquidator or
     assignee, custodian, trustee, sequestrator (or similar official) of Tenant
     or any substantial part of its property, or seeking the winding-up or
     liquidation of its affairs and such involuntary case or petition is not
     dismissed within 60 days after the filing thereof, or if Tenant commences a
     voluntary case or institutes proceedings to be adjudicated a bankrupt or
     insolvent, or consents to the institution of bankruptcy or insolvency
     proceedings against it, under the Federal bankruptcy laws as now or
     hereafter constituted, or any other applicable Federal or state bankruptcy
     or insolvency or other similar law, or consents to the appointment of or
     taking possession by a receiver or liquidator or assignee, trustee,
     custodian, sequestrator (or other similar official) of Tenant or of any
     substantial part of its property, or makes any assignment for the benefit
     of creditors or admits in writing its inability to pay its debts generally
     as they become due or fails to generally pay its debts as they become due
     or if Tenant or its stockholders or board of directors or any committee
     thereof takes any corporate action in contemplation, preparation or
     furtherance of or for any of the occurrences, steps, procedures,
     proceedings or other items mentioned in this Paragraph 21(b) or

          (c) if Tenant shall vacate and abandon the Premises for a period of
     seven consecutive days during the Term, Landlord may treat the occurrence
     of any one or more of the foregoing events as a breach of this Lease, and
     thereupon at its option may, without notice or demand of any kind to Tenant
     or any other person, have any one or more of the

                                       19
<PAGE>

     following described remedies in addition to all other rights and remedies
     provided at law or in equity or elsewhere herein:

               (i)   At the option of Landlord, the whole balance of rent,
          charges and all other sums payable hereunder, whether or not payable
          as rent, for the entire balance of the Term, and any renewal or
          extension thereof, herein reserved or agreed to be paid by Tenant, or
          any part of such rent, charges and other sums, and also all or any
          costs and sheriffs, marshall's, constable's or other official's fees
          and charges, whether chargeable to Landlord or Tenant, shall be taken
          to be due and payable from Tenant and in arrears as if by the terms of
          this Lease said balance of rent, charges and other sums and expenses
          were on that date payable in advance; and/or

               (ii)  Landlord, by giving written notice to Tenant, may terminate
          this Lease and the Term, in which event Landlord may immediately
          repossess the premises by legal proceedings, force or otherwise;
          and/or

               (iii) Landlord, by giving written notice to Tenant, may terminate
          Tenant's right of possession and may immediately repossess the
          Premises by legal proceedings, force or otherwise, without terminating
          this Lease.

               (iv)  After reentry, retaking, repossessing or recovering of the
          Premises, whether or not Landlord has terminated this Lease, Landlord
          may, but shall be under no obligation to, relet the same or any
          portion thereof for such rent and upon such terms as shall be deemed
          advisable by Landlord; and whether or not the Premises are relet,
          Tenant shall be liable for any loss of rent for such period as would
          be the balance of the term of this Lease and any renewals thereof plus
          the costs and expenses of reentry, retaking, repossession and
          recovering, and of reletting and of redecorating, remodeling and
          making repairs and alterations to the Premises for the purpose of
          reletting, the amount of such liability to be computed monthly and
          paid by Tenant to Landlord at the end of each month. Landlord shall in
          no event have any duty to relet the Premises, nor shall any damages or
          other sums to be paid by Tenant to Landlord be reduced by any failure
          to relet the Premises or failure to collect the rent from any
          reletting. Tenant shall not be entitled to any rents received by
          Landlord in excess of the rents provided for in this Lease. Tenant
          agrees that Landlord may file suit to recover any sums falling due
          under the terms of this Paragraph 21 from time to time and that no
          suit or recovery of any portion due Landlord hereunder shall be any
          defense to any subsequent action brought for any amount not
          theretofore reduced to judgment in favor of Landlord. If Landlord
          relets the Premises, such reletting shall not be considered a
          termination of this Lease unless Landlord has given Tenant a notice
          wherein Landlord expressly states that this Lease is terminated.

               (v)   If Landlord shall terminate this Lease as provided in
          subparagraph (b) above, Landlord, at its option, shall be entitled to
          recover as damages the excess, if any, at the time of such
          termination, of the amount of the Base Rent payable under this lease
          for the balance of the term of this Lease (including, any extension
          options which have been exercised) over the then fair rental value of
          the Premises for the same period, plus all costs and expenses of
          Landlord caused by Tenant's default, including, but not limited to,
          reasonable attorney's fees.

               (vi)  If any payment of rent or any other sum, or any part of any
          such payment to be made by Tenant under the terms of this Lease shall
          become overdue for a period in excess of five days Tenant shall pay to
          Landlord (x) a "late charge" of $.05 for each dollar so overdue, for
          the purpose of defraying the expense incident to handling such overdue
          or delinquent payment, and (y) interest on the overdue amount at the
          Least Interest Rate (defined below) from the date when such payment
          was due until the date paid, but in no event more than the amount or
          rate which is the maximum amount or rate Landlord may lawfully charge
          in respect of Tenant in such circumstances under applicable law. The
          "Lease Interest Rate" shall mean the greater of 18% per annum or such
          variable rate which is from time to time equal to 3% above

                                       20

<PAGE>

          the prime rate as stated by Colorado National Bank, Denver, Colorado
          or its successor, or, in the absence of there being a successor to
          Colorado National Bank, by such other bank having an office in the
          City of Denver, as Landlord may from time to time select. Nothing
          herein shall be construed as waiving any rights of Landlord arising
          out of any default of Tenant by reason of Landlord's accepting any
          such late charge or interest; the right to collect a late charge and
          interest is separate and apart from any other rights or remedies of
          Landlord after default by Tenant.

               (vii)  Without limiting the generality of the foregoing, if
          Tenant shall be in default in the performance of any of its
          obligations hereunder, Landlord may (but shall not be obligated to),
          in addition to any other rights it may have in law or in equity, cure
          such default on behalf of Tenant, and Tenant shall reimburse Landlord
          upon demand for any sums paid or costs incurred by Landlord in curing
          such default, including reasonable attorneys' fees and other legal
          expenses, together with interest at the Lease Interest Rate from the
          dates of Landlord's incurring of costs or expenses.

               (viii) All remedies available to Landlord hereunder and
          otherwise available at law or in equity shall be cumulative and
          concurrent. No termination of this Lease nor taking or recovering
          possession of the Premises shall deprive Landlord of any remedies or
          actions against Tenant for rent, for charges, or for damages for the
          breach of any term, covenant or condition herein contained, nor shall
          the bringing of any such action for rent, charges or breach of term,
          covenant or condition, nor the resort to any other remedy or right for
          the recovery of rent, charges or damages for such breach be construed
          as a waiver or release of the right to insist upon the forfeiture and
          to obtain possession. The failure of Landlord to insist upon strict
          and/or prompt performance of the terms, agreements, covenants and
          conditions of this Lease or any of them, and/or the acceptance of such
          performance thereafter shall not constitute or be construed as a
          waiver of Landlord's right to thereafter enforce the same strictly
          according to the tenor thereof in the event of a continuing or
          subsequent default.

               (ix)   Notwithstanding anything in this Paragraph 21 or any other
          provision of this Lease to the contrary, this Lease shall not be
          terminated by service upon Tenant of a notice from Landlord demanding
          payment of rent or possession of the Premises following default by
          Tenant, or by any action of Tenant to vacate the Premises following
          receipt of such a notice, unless the notice served by Landlord
          includes a statement expressly terminating this Lease. Further,
          Landlord reserves the right to receive payment of all unaccrued rent
          for the balance of the Term originally contemplated under Paragraph 1
          of this Lease (and any extensions or renewals thereof to which Tenant
          shall have become bound) following service of such a notice for
          payment or possession, or a notice terminating this Lease for Tenant's
          default.

     22.  Expenses of Enforcement.  Tenant shall pay upon demand all Landlord's
costs, charges and expenses, including the fees and out-of-pocket expenses of
counsel, agents and others retained by Landlord, incurred by Landlord, whether
or not suit is brought, in enforcing Tenant's obligations hereunder or in
collecting any amounts due from Tenant or any subtenant or assignee hereof or in
enforcing any provision of this Lease or in any litigation, negotiation or
transaction in which Tenant causes Landlord without the Landlord's fault to
become involved or concerned or in reletting the Premises or any portion thereof
after default by Tenant.  Landlord and Tenant further agree that in the event
any legal action or proceeding is commenced to enforce the obligations set forth
in this Lease, the prevailing party shall be entitled to an award of all
reasonable costs and expenses including, but not limited to, reasonable
attorneys' fees.

     23.  Covenant of Quiet Enjoyment.  Landlord covenants that Tenant, on
paying the rent, charges for services and other payments herein reserved or
required and on keeping, observing and performing all the other terms,
covenants, conditions, provisions and agreements herein contained on the part of
the Tenant to be kept, observed and performed, shall, during the Term, peaceably
and quietly have, hold and enjoy the Premises free from interference by Landlord
or any person claiming by, from or under Landlord, subject, however, to the
terms, covenants, conditions, provisions and agreements hereof.

                                       21

<PAGE>

     24.  Security Deposit.  Upon the execution of this Lease, Tenant shall
deposit with Landlord the sum of $11,018.67 (hereinafter referred to as
"Collateral"), as security for the prompt, full and faithful performance by
Tenant of each and every provision of this Lease and of all obligations of
Tenant hereunder.  No interest shall be paid to Tenant on the Collateral and
Landlord may commingle the collateral with any other funds of Landlord.

     If Tenant fails to perform any of its obligations hereunder, Landlord may
use, apply or retain the whole or any part of the Collateral for the payment of
(a) any rent or other sums of money which Tenant may not have paid when due, (b)
any sum expended by Landlord on Tenant's behalf in accordance with the
provisions of this Lease, and/or (c) any damages which Landlord may sustain or
sums which Landlord may expend or be required to expend by reason of Tenant's
default, including, without limitation, any damage or deficiency in or from the
reletting of the Premises as provided in Paragraph 21.  The use, application or
retention of the Collateral, or any portion thereof, by Landlord shall not
prevent Landlord from exercising any other right or remedy provided by this
Lease or by law (it being intended that Landlord shall not first be required to
proceed against the Collateral) and shall not operate as a limitation on any
recovery to which Landlord may otherwise be entitled.  If any portion of the
Collateral is used, applied or retained by Landlord for the purposes set forth
above, Tenant agrees, within ten days after the written demand therefore is made
by Landlord, to deposit cash with the Landlord in an amount sufficient to
restore the Collateral to its original amount.

     If Tenant shall fully and faithfully comply with all of the provisions of
this Lease, the Collateral, or any balance thereof, shall be returned to Tenant
without interest within 30 days after the expiration of the Term or within 30
days after the date Tenant has vacated the Premises.  In the absence of evidence
satisfactory to Landlord of any permitted assignment of the right to receive the
Collateral, or of the remaining balance thereof, Landlord may return the same to
the original Tenant, regardless of one or more assignments of Tenant's interest
in this Lease or the Collateral.  In such event, upon the return of the
Collateral, or the remaining balance thereof to the original Tenant, Landlord
shall be completely relieved of liability under this Paragraph 24 or otherwise
with respect to the Collateral.

     Tenant acknowledges that Landlord has the right to transfer or mortgage its
interest in the Property and in this Lease and Tenant agrees that in the event
of any such transfer or mortgage, Landlord shall have the right to transfer or
assign the Collateral to the transferee or mortgagee.  Upon written
acknowledgment of transferee's or mortgagee's receipt of such Collateral,
Landlord shall thereby be released by Tenant from all liability or obligation
for the return of such Collateral and Tenant shall look solely to such
transferee or mortgagee for the return of the Collateral.

     The Collateral shall not be mortgaged, assigned or encumbered in any manner
whatsoever by Tenant.

     25.  Real Estate Broker.  Landlord and Tenant acknowledge and agree that:
(i) Landlord has been represented in connection with this Lease by the Agent as
Landlord's agent and by Garth R. D. Tait, Broker, Ltd. ("Tait") as Landlord's
subagent, and (ii) Tenant has been represented in connection with this Lease by
Liberty Partners Inc. (Bruce Johnson and Alex Hammerstein) ("Liberty Partners")
as Tenant's agent. Tenant agrees to indemnify, defend and hold Landlord harmless
from and against any claims, for a commission or other compensation in
connection with this Lease, made by any broker or finder (other than Agent, Tait
and Liberty Partners) who claim to have dealt with or communicated to Tenant in
connection with this Lease provided that Landlord has not in fact retained such
broker or finder.  Landlord agrees to pay Agent, Tait and Liberty Partners
pursuant to the terms of separate agreements, for their services rendered in
connection with this Lease, and agrees to indemnify, defend and hold Tenant
harmless from and against any claims, for a commission or other compensation in
connection with this Lease, made by any broker or finder who claim to have dealt
with or communicated to Landlord in connection with this Lease provided that
Tenant has not in fact retained such broker or finder.

                                       22
<PAGE>

     26.  Miscellaneous.

          (a) Rights Cumulative.  All rights and remedies of Landlord under this
              -----------------
Lease shall be cumulative and none shall exclude any other rights or remedies
allowed by law, in equity or otherwise.

          (b) Captions and Usage.  The titles appearing in connection with the
              ------------------
various sections and paragraphs of this lease are for convenience only; they are
not intended to indicate all of the subject matter in the text and they are not
to be used in interpreting this Lease nor for any other purpose in the event of
any controversy.  As used herein (i) the term "person" shall be deemed to
include a natural person, a trustee, a corporation, a partnership, a
governmental unit and any other form of legal entity; (ii) all usages in the
singular or plural number shall be deemed to have been made, respectively, in
the plural or singular number as well; the use of any gender includes all
genders.

          (c) Binding Effect.  Each of the provisions of this Lease shall extend
              --------------
to and shall, as the case may require, bind or inure to the benefit not only of
the Landlord and of Tenant, but also of their respective successors or assigns,
provided this clause shall not permit any assignment by Tenant contrary to the
provisions of Paragraph 15 hereof.

          (d) Lease Contains All Terms.  There are no promises, representations,
              ------------------------
warranties or undertakings by, or binding upon, Landlord with respect to the
Building, the Premises or the Real Property, including, but not limited to, any
with regard to alteration, remodeling, redecorating or installation of equipment
or fixtures in the Premises, except those, if any, that are expressly set forth
in this Lease.  No modification, waiver or amendment of this Lease or of any of
its conditions or provisions shall be binding upon the Landlord unless in
writing signed by Landlord or by a duly authorized agent of Landlord empowered
by a written authority signed by Landlord.

          (e) Submission of Lease.  Submission of this Lease by Landlord for
              -------------------
execution by Tenant, or Tenant's execution hereof without Landlord's prior or
simultaneous execution, shall not bind Landlord in any manner, and no binding
Lease or obligation of the Landlord shall arise until Lease is signed by both
Landlord and Tenant and delivery is made to each.

          (f) No Air Rights.  No rights to any view or to light or air over any
              -------------
property whether belonging to Landlord or any other person, are granted to
Tenant by this Lease.

          (g) Modification of Lease.  If any lender requires, as a condition to
              ---------------------
its lending funds, the repayment of which is to be secured by a mortgage or
trust deed on the Property or any part thereof, that certain modifications be
made to this Lease, which modifications will not require Tenant to pay any
additional amounts or otherwise change materially the rights or obligations of
Tenant hereunder, Tenant shall, upon Landlord's request, execute appropriate
instruments effecting such modifications.

          (h) Substitution of Other Premises.
              ------------------------------

              (i)   In the event Tenant exercises the Renewal Option
          (hereinafter defined) and Tenant occupies less than all the rentable
          area located on the fifth (5th) floor of the Building, Landlord shall
          have the right during the Renewal Term to substitute for the premises
          then being leased or to be leased hereunder (the "Existing Premises")
          other premises within the Building (herein referred to as the "New
          Premises") provided that the New Premises shall be of at least
          substantially the same size and shall either have substantially the
          same perimeter configuration or a perimeter configuration
          substantially as usable for the purposes for which the Existing
          premises were being used by tenant.

               (ii) Tenant shall vacate and surrender the Existing Premises not
          later than the later of the 30th day after the date that Landlord
          shall notify Tenant of Landlord's intent to make the substitution in
          question or the 15th day after landlord shall have

                                       23
<PAGE>

          substantially completed the work to be done by Landlord in the New
          Premises pursuant to this subparagraph (ii). As of the sooner of such
          15th day or the date of such surrender and vacation, the New Premises
          shall be the Premises leased under this Lease and the Existing
          Premises shall cease to be the Premises leased under this Lease.
          Landlord shall (A) pay the actual and reasonable out-of-pocket
          expenses of Tenant's moving of its property from the Existing Premises
          to the New Premises, including but not limited to, Tenant fixtures,
          furniture, filing systems, movable partitions, modules, computer and
          telephone cabling, and equipment, (B) pay the cost and expense of
          reprinting reasonable quantities of stationery, business cards,
          advertising and promotional materials, and (C) shall improve the New
          Premises so that they are substantially similar to the Existing
          Premises and promptly reimburse Tenant for its actual and reasonable
          out-of-pocket costs in connection with the relocation of any telephone
          or other communications equipment from the Existing Premises to the
          New Premises. However, instead of only paying the expenses of Tenant's
          moving of its property, Landlord may elect to either move Tenant's
          property or provide personnel to do so under Tenant's direction, in
          which event such move may not be made except during evenings, weekends
          or holidays, so as to incur the least inconvenience to Tenant.

               (iv)  Tenant shall not be entitled to any compensation for any
          inconvenience or interference with Tenant's business, nor to any
          abatement or reduction in rent, nor shall Tenant's obligations under
          this Lease be otherwise affected, as a result of the substitution
          except as otherwise provided in this subparagraph (h). Tenant agrees
          to cooperate with Landlord so as to facilitate the prompt completion
          by Landlord of, its obligations under this subparagraph (h). Without
          limiting the generality of the preceding sentence, Tenant agrees to
          provide to Landlord promptly such approvals, instructions, plans,
          specifications or other information, as may be reasonably requested by
          Landlord.

          (i)  Transfer of Landlord's Interest.  Notwithstanding anything
               -------------------------------
contained herein to the contrary, Tenant agrees that neither Landlord nor any
partner in Landlord, nor any other person having any interest, direct or
indirect, immediate or more removed than immediate, in Landlord, shall have any
personal liability with respect to any of the provisions of this Lease and
Tenant shall look solely to the estate and property of Landlord in the Property
for the satisfaction of Tenant's remedies, including without limitation, the
collection of any judgment or the enforcement of other judicial process
requiring the payment or expenditure of money by Landlord, subject, however, to
the prior rights of any holder of any mortgage covering all or part of the
Property, and no other assets of Landlord or its partners, or of any other
aforesaid person having an interest in Landlord, shall be subject to levy,
execution or other judicial process for the satisfaction of Tenant's claims.
Without limitation of the foregoing, upon each transfer of the Building and the
Landlord's interest in this Lease, the transferor shall automatically be
released from all liability and obligations under this Lease.

          (j)  Recording; Short Form Memo. This Lease shall not be recorded by
               --------------------------
Tenant. If it is recorded by Tenant, Landlord shall have the right to terminate
this Lease as of the date of recording or thereafter and Landlord shall have all
rights and remedies provided in the case of default by Tenant hereunder. If
requested by Landlord, Tenant shall execute, in recordable form, a short form
memorandum of lease that may, at Landlord's option, be placed of record. In
addition, if requested by Landlord, Tenant shall execute a memorandum of lease
to be filed with the Colorado Department of Revenue, on such form as may be
prescribed by said Department, within ten days after the execution of this
Lease, or any other such memorandum, so that the Landlord may avail itself of
the provision of statutes such as C.R.S. 1973 39-22-604(7)(c).

          (k) Covenants and Conditions.  All of the covenants of Tenant
              ------------------------
hereunder shall be deemed and construed to also be "conditions", if Landlord so
elects, as well as "covenants" as though the words specifically expressing or
importing covenants and conditions were used in each separate instance. Tenant's
covenants to pay rent are independent of any other covenant, agreement, term or
condition of this Lease.

                                       24
<PAGE>

          (l)  Application of Payments.  Landlord shall have the right to apply
               -----------------------
payments received from Tenant pursuant to this Lease (regardless of Tenant's
designation of such payments) to satisfy any obligations of Tenant hereunder, in
such order and amounts as Landlord in its sole discretion, may elect.

          (m)  Security Interest and Tenant's Deposit.
               --------------------------------------

               (i)   As security for the payment of all rent and other sums
          becoming due under this Lease and the performance of all of Tenant's
          obligations under this Lease, Tenant hereby grants to Landlord a
          security interest in all improvements, equipment and other personal
          property of Tenant situated on or in the Premises excluding computer
          software and Tenant's business records. Such security interest shall
          at all times be subordinate to (i) any currently existing or future
          purchase money finance relating to such improvements, equipment and
          other personal property and (ii) any currently existing or future
          security interest granted for the benefit of any lender providing
          financing to the Tenant or other entity with an ownership interest in
          the equipment. Tenant within 15 days after request therefore made from
          time to time by Landlord shall execute such documents as Landlord may
          reasonably request in order to evidence and perfect Landlord's
          security interest; provided, however, Landlord agrees that no
          financing statement shall be filed if prohibited by the holder of a
          permitted prior security interest. If Tenant is in default under this
          Lease, such improvements, equipment and other personal property shall
          not be removed from the Premises without the prior written consent of
          Landlord. Upon any default by Tenant under this Lease, Landlord may
          exercise any and all rights of a secured party under the Colorado
          Uniform Commercial Code.

               (ii)  Tenant represents that from the expiration of the third
          month of the Term of this Lease throughout the Term of this Lease,
          Tenant and its parent company, Prime Response Group, Inc. ("Prime
          Response Group") shall collectively maintain, at all times during the
          Term of this Lease, banking deposits (the "Deposits") in federal or
          state chartered United States financial institutions in an aggregate
          amount of not less than One Million and No/100 Dollars ($1,000,000.00)
          (the "Minimum Deposit"). Provided that Tenant timely performs all of
          its obligations under this Lease arising through and including the
          eighteenth (18th) month of the Term the amount of the required Minimum
          Deposit shall be reduced to an aggregate amount of not less than Five
          Hundred Thousand and No/100 Dollars ($500,000.00) Tenant shall provide
          Landlord during the Term of the Lease within ten (10) days after
          receipt of such request from Landlord, with such documentation
          reasonably required by Landlord to evidence that Tenant and Prime
          Response Group are maintaining the Deposits required under this
          subparagraph. The Deposits shall not be pledged as collateral for
          additional security hereunder; provided, however, that notwithstanding
          the foregoing, it shall constitute a default under the Lease if the
          Deposits fall below the Minimum Deposit at any time during the Term of
          this Lease.

          (n)  Governing Law; Partial Invalidity.  This Lease shall be governed
               ---------------------------------
and construed in accordance with the law of the state in which the Premises is
located.  If any term, provision or condition contained in this Lease shall, to
any extent, be invalid or unenforceable, the remainder of this Lease (or the
application of such term, provision or condition to persons or circumstances
other than those in respect of which it is invalid or unenforceable) shall not
be affected thereby, and each and every other term, provision and condition of
this Lease shall be valid and enforceable to the fullest extent possible
permitted by law.

          (o)  Hazardous Materials.  Tenant shall not store highly flammable
               -------------------
materials or goods, explosives, perishable foodstuffs, contraband, live animals,
materials or goods which emit odors in or upon the Premises.  The Tenant
covenants that it shall not store, use or posses nor permit the storage, use or
possession of any Hazardous Substance (hereinafter defined) upon the Premises,
except of the kind and in the quantities customarily used in commercial office
buildings provided that Tenant complies with all Environmental Laws (hereinafter
defined).  Hazardous Substance for purposes of this Lease shall mean, without

                                       25
<PAGE>

     limitation, any flammable explosives, radon, radioactive materials,
     asbestos, urea-formaldehyde foam insulation, polychlorinated biphenyls,
     petroleum and petroleum based products, methane, hazardous materials,
     hazardous wastes, hazardous or toxic substances or related materials, as
     defined in the Comprehensive Environmental Response, Compensation and
     Liability Act of 1980, as amended (42 U.S.C. Sections 9601 et seq.), the
                                                                ------
     Hazardous Materials Transportation Act, as amended (49 U. S.C. Section
     1801, et seq.), Sections 6901, et seq.), the Toxic Substances Control Act,
           ------                   ------
     as amended (15 U.S.C. Sections 2601 et seq. or any other similar law,
                                         ------
     rules, regulation or statute concerning the protection of the environment
     (collectively "Environment Laws"). Tenant hereby covenants and agrees, at
     its sole cost and expense, to indemnify, protect and defend and save
     harmless the Landlord and any of its partners, employees and agents from
     and against any all damages, losses, liabilities, obligations, penalties,
     claims, litigation, demands, defenses, judgments, suites, actions,
     proceedings, costs, disbursements and/or expenses (including, without
     limitation, attorneys' and experts' fees, expenses and disbursements) of
     any kind or nature whatsoever which may at any time impose upon, incurred
     by or asserted or awarded against the Landlord, its partners, agents or
     employees to the extent it relates to, results from or arises out of
     Tenant's failure to comply with its obligations under the foregoing
     paragraph or Tenant's violation of any Environmental Law with respect to
     its use of the Premises. Notwithstanding any provision contained in this
     Lease to the contrary, the indemnification provisions set forth in this
     paragraph shall survive any expiration and/or termination of this Lease.

     27.  Telephone and Telecommunications Service.

          (a) Tenant acknowledges and agrees that all telephone and
     telecommunications services ("Telecommunications Services") desired by
     Tenant shall be ordered and utilized at the sole expense of Tenant. Unless
     Landlord otherwise requests or consents in writing, all equipment,
     apparatus and devices, including without limitation wiring and cables, for
     the provisions of Telecommunications Services (the "Telecommunications
     Equipment") shall be and remain solely in the Leased Premises. Unless
     otherwise specifically agreed in writing, Landlord shall have no
     responsibility for the maintenance of Tenant's Telecommunications
     Equipment, nor for any wiring or other infrastructure to which Tenant's
     Telecommunications Equipment may be connected. Tenant agrees that, to the
     extent any Telecommunications Services are interrupted, curtailed or
     discontinued, Landlord shall have no obligation or liability with respect
     thereto and it shall be the sole obligation of Tenant, at its sole expense,
     to obtain substitute service.

          (b) Landlord shall have the right, upon such notice as is practicable
     in the case of emergencies, and otherwise upon reasonable prior notice to
     Tenant, to interrupt or turn off telecommunications facilities in the event
     of emergency or as necessary in connection with repairs to the Building or
     installation of telecommunications equipment for other tenants of the
     Building.

          (c) Any and all Telecommunications Equipment installed in the
     Premises, or elsewhere in the Building by or on behalf of Tenant, including
     wiring and other facilities for the provision of Telecommunications
     Services, shall be removed by Tenant upon the expiration or earlier
     termination of the Term of this Lease, by Tenant at its sole expense or, at
     Landlord's election, by Landlord at Tenant's sole expense, with the cost
     thereof to be paid as Additional Rent under this Lease.

          (d) If the Telecommunications Equipment is not removed within thirty
     (30) days of the termination or expiration of this Lease, the
     Telecommunications Equipment shall conclusively be deemed to have been
     abandoned and may be removed, appropriated, sold, stored, destroyed,
     otherwise disposed of, or retained and used, by landlord without notice to
     Tenant, without obligation to account therefor, and without payment to
     Tenant or credit against any amount due from Tenant to Landlord pursuant to
     this Lease. Tenant shall pay to Landlord upon demand all costs of any such
     removal, disposition and storage of the Telecommunications Equipment, as
     well as all costs to repair any damage to the Building caused by such
     removal.

                                       26
<PAGE>

          (e) In the event that Tenant wishes at any time to utilize the
     services of a telephone or telecommunications provider whose equipment is
     not then servicing the Building (a "New Provider"), no such New Provider
     shall be permitted to install its lines or other equipment within the
     Building without first securing the prior written approval of the Landlord,
     which approval may be withheld in Landlord's sole and absolute discretion.
     Landlord's approval shall not be deemed any kind of warranty or
     representation by Landlord, including, without limitation, any warranty or
     representation as to the suitability, competence or financial strength of
     the New Provider. Without limitation of Landlord's right to withhold
     consent in its sole and absolute discretion, Landlord may refuse to give
     its approval unless all of the following conditions are satisfied: (i)
     Landlord shall incur no expense whatsoever with respect to any aspect of
     the New Provider's provision of its services, including, without
     limitation, the costs of installation, materials and services; (ii) prior
     to commencement of any work in or about the Building by the New Provider,
     the New Provider shall supply Landlord with such written indemnities,
     insurance, financial statements, and such other items as Landlord, in its
     sole and absolute discretion, determines to be necessary to protect its
     financial interests and the interests of the Building related to the
     proposed activities of the New Provider; (iii) the New Provider agrees in
     writing to abide by such rules and regulations, building and other codes,
     job site rules and such other requirements as are determined by Landlord,
     in its sole and absolute discretion, to be necessary to protect the
     interest of the Building, the tenants in the Building and Landlord; (iv)
     Landlord determines, in its sole and absolute discretion, that there is
     sufficient space in the Building for the placement of all of the New
     Provider's equipment and materials; (v) Landlord receives from the New
     Provider such compensation as is determined by the Landlord, in its sole
     and absolute discretion, to compensate it for space used in the Building
     for the storage and maintenance of the New Provider's equipment, for the
     fair market value of the New Provider's access to the Building, and any
     costs which may be expected to be incurred by Landlord; and (vi) all of the
     foregoing matters are documented in a written agreement between Landlord
     and the New Provider, the form and content of which are satisfactory to
     Landlord in its sole and absolute discretion.

          (f) Notwithstanding any provision of the preceding subsection to the
     contrary, the refusal of Landlord to grant its approval to any New Provider
     shall not be deemed a default or breach by Landlord of its obligation under
     this Lease, and in no event shall Tenant have the right to terminate this
     Lease or claim entitlement to rent abatement for Landlord's refusal to
     grant Tenant's request for approval of a New Provider. The provisions of
     this Section 27 may be enforced solely by Tenant and Landlord and are not
     for the benefit of any other party. Specifically, but without limitation,
     no telephone or telecommunications provider is intended to be, nor shall be
     deemed, a third party beneficiary of this Lease.

          (g) Tenant shall not utilize any wireless communications equipment
     (other than usual and customary cellular telephones), including antenna and
     satellite receiver dishes, within the Leased Premises or the Building,
     without Landlord' prior written consent. Such consent shall be granted only
     in the sole and absolute discretion of the Landlord, and shall be
     conditioned in such a manner, in Landlord's sole and absolute discretion,
     so as to protect Landlord's financial interests and the interests of the
     Building, and the other tenants therein. Notwithstanding the foregoing
     provisions of this paragraph 27(g), Landlord agrees not to unreasonably
     withhold its consent to Tenant's use of wireless communications equipment
     for the purpose of communicating between Tenant's equipment located within
     the Premises provided the use of such wireless communications equipment (i)
     does not create a risk to the health and safety of Tenant's employees or
     any other occupants of the Building and (ii) does not interfere with any
     other tenant's use and enjoyment of their premises within the Building. In
     the event Landlord determines that any wireless communications equipment
     used by Tenant in the Premises which was previously consented to by
     Landlord either (i) poses a risk to the health or safety of Landlord's
     employees or any other occupants of the Building or (ii) interferes with
     some other tenant's use of its premises. Tenant shall immediately, upon
     receipt of notice from Landlord, cease the operation of such wireless
     communications equipment and promptly thereafter remove the same from the
     Premises.

                                       27
<PAGE>

     28.  Notices.  All notices to be given under this Lease shall be in writing
and delivered personally or deposited in the United States mail, certified or
registered mail with return receipt requested, postage prepaid, addressed as
follows:

          If to Landlord:

               Amerimar Realty Management Co.-Colorado
               999 - 18th Street, Suite 1000
               Denver, Colorado 80202

     or to such other person or such other address designed by notice sent by
     Landlord or Tenant.

          If to Tenant:

               At the address set forth at the beginning of this Lease,

and after occupancy of the Premises by Tenant, at the Premises, or to such other
address as is designated by Tenant in a notice to Landlord; it being agreed that
if Tenant shall vacate the Premises, notices to Tenant thereafter shall
nevertheless be properly given if addressed to Tenant at the Premises unless and
until another address is designated by Tenant by notice to Landlord.

     Notice by mail shall be deemed to have been given when deposited in the
United States mail as aforesaid.

     29.  Time is of the Essence.  Time is of the essence hereof.

          IN WITNESS WHEREOF, Landlord and Tenant, intending to be legally bound
hereby, have executed this Agreement of lease as of the day and year first above
written.

                                     LANDLORD:

                                     DENVER-STELLAR ASSOCIATES
                                     LIMITED PARTNERSHIP, a Delaware
                                     limited partnership

                                     By:  Amerimar Realty Management Co.-
                                          Colorado

                                          By:  Amerimar Realty Management-
                                               Pennsylvania, its general partner

                                               By:  ARC-Management
                                                    Company, its general
                                                    partner,

                                     By:  /s/ David G. Marshall
                                          --------------------------------------
                                              David G. Marshall, President

                                     TENANT:

                                     PRIME RESPONSE, INC., a Delaware
                                     corporation

                                     By: /s/ [ILLEGIBLE] CEO
                                        ----------------------------------------
                                               Authorized Signature (Title)

                                       28
<PAGE>

                                   ADDENDUM

     THIS ADDENDUM, made as of the 20th day of January, 1998, is between DENVER-
STELLAR ASSOCIATES LIMITED PARTNERSHIP, a Delaware limited partnership
("Landlord") and PRIME RESPONSE, INC., a Delaware corporation ("Tenant").
Landlord and Tenant have executed simultaneously with this Addendum that certain
Denver Place Office Lease (the "Lease") pertaining to certain space in the
building commonly known as Denver Place and located at 1099 Eighteenth Street,
Denver, Colorado.  In the event of any conflict between the provisions of this
Addendum and the provisions of the other portions of the lease, the provisions
of this Addendum shall control.  The capitalized terms used herein and not
defined herein shall have the same meanings used in the other portions of the
Lease.  Landlord and Tenant hereby agree that the Lease is amended and
supplemented as follows:

     30.  Completion of Premises.

          (a)  Phase One Premises:
               -------------------

                (i)  Landlord shall, at its own cost and expense, in a good and
          workmanlike manner, cause the Phase One Premises to be improved and
          completed in accordance with those certain construction drawings
          prepared by burkettdesign, inc. dated December 15, 1997 and revised
          December 19, 1997 consisting of pages 5AO, 5AI, 5A2, 5A3, 5A4, 5A61,
          5A62, E 1.0, E2.0, E3.0, M 1.1, P 1.0 and FP 1.0 (collectively the
          "Phase One Final Layout Plans") attached as Exhibit A (such work being
                                                      ---------
          herein called "Phase One Landlord's Work"). Landlord reserves the
          right, however: [A] to make substitutions of material or components of
          equivalent grade and quality when and if any specified material or
          component shall not be readily or reasonably available, and [B] to
          make changes necessitated by conditions met in the course
          of construction, provided that Tenant's approval of any substantial
          change shall first be obtained (which approval shall not be
          unreasonably withheld or delayed so long as there shall be general
          conformity with the substance and quality contemplated by the Phase
          One Final Layout Plans). The provisions of the Workletter attached
          hereto as Exhibit E are incorporated herein by this reference.
                    ---------

               (ii)  If Landlord shall, for any reason (including, without
          limitation, failure to complete the work, if any, required to be done
          by Landlord under this Lease) fail to make available to Tenant
          possession of the Phase One Premises on or before the Scheduled
          Commencement Date or any other date, Landlord shall not be subject to
          any liability for such failure nor for any failure to timely complete
          any work. Under such circumstances, Tenant's obligations to pay Base
          Rent, the Expense Adjustment Amount and Tax Adjustment Amount shall
          not commence until the date Tenant is permitted to occupy the Phase
          One Premises for the operation of its business by the City and County
          of Denver ("Ready for Occupancy") and such failure to cause the Phase
          One Premises to be made Ready for Occupancy on or before the Scheduled
          Commencement Date or any other date or to timely complete any work,
          shall not in any other way affect the validity or continuance of this
          Lease, nor the Term or the obligations of Tenant hereunder. Such
          deferral of rent shall be Tenant's sole and exclusive right and remedy
          with respect to any such failure; provided, however, that in the event
          the Phase One Premises are not Ready for Occupancy on or before May 1,
          1998, Tenant shall have the right to terminate this Lease provided
          Tenant delivers written notice to Landlord exercising such right on or
          before May 10, 1998 or the date the Phase One Premises are Ready for
          Occupancy, whichever occurs first. Notwithstanding the foregoing,
          there shall be no deferral of rent and Tenant shall not have the right
          to terminate this Lease, however, if any such failure is caused in
          whole or part by any act or omission of Tenant, its agency, servants,
          employees or contractors, which has the effect of hindering or
          delaying Landlords' delivery of possession or the timely completion of
          any work to be done by Landlord (hereinafter a "Phase One Tenant
          Delay") including, without limitation, [A] any delay which is caused
          by changes in the work to be performed by Landlord in readying the
          Phase One Premises for Tenant's occupancy, [B] any delay, not caused
          by Landlord, in

                                       29
<PAGE>

          furnishing materials or procuring labor required to be furnished or
          procured for the completion of the Phase One Premises, or [C] any
          delay which is caused by any failure by Tenant, without regard to any
          grace period applicable thereto, promptly to furnish to Landlord any
          required information, approval or consent or caused by any good faith
          reluctance on the part of Landlord to approve any information required
          to be submitted by Tenant and approved by Landlord, or [D] any delay
          which is caused by the performance of any work or activity in the
          Phase One Premises by Tenant or any of its employees, agents or
          contractors. Tenant also shall pay to Landlord, within 10 days after
          receipt of demand made from time to time (accompanied by documentation
          evidencing such costs and expenses), a sum equal to any reasonable
          additional costs and expenses incurred by Landlord in completing the
          Phase One Premises resulting from any Phase One Tenant Delay.

               (iii)  Landlord shall provide an allowance (the "Phase One
          Construction Allowance") for the payment of the costs and expenses of
          completing the Phase One Landlord's Work in an amount up to One
          Hundred Twenty-Eight Thousand Seven Hundred Forty and No/100 Dollars
          ($128,740.00). The Phase One Construction Allowance shall include but
          not be limited to all architectural and engineering fees, all costs of
          Phase One Landlord's Work (from slab to slab), permit fees, Landlord
          supervision fee of 3% and contractor overhead costs. Tenant shall be
          responsible for the payment of all Phase One Landlord's Work in excess
          of the Phase One Construction Allowance (the "Excess Phase One Tenant
          Costs") which excess shall be payable within thirty (30) days after
          Tenant's receipt of a written request from Landlord which request
          shall be accompanied by a calculation of the Phase One Excess Tenant
          Costs in reasonable detail. If the cost of completing the Phase One
          Landlord's Work is less than Phase One Construction Allowance, the
          portion of the Phase One Construction Allowance not used (the "Phase
          One Construction Allowance Remainder") shall be paid, at Landlord's
          sole discretion, in one of the following manners: [A] the entire Phase
          One Construction Allowance Remainder shall be paid directly to Tenant
          on or before the last day of the fifteenth (15th) month of the Term of
          the Lease, or [B] Tenant shall receive a credit upon the monthly Base
          Rent payable by Tenant in accordance with the provisions of Paragraph
          2 in an amount equal to the quotient of the amount of the Phase One
          Construction Allowance Remainder divided by sixty-six (66) (66 being
          the number of months in the Term).

          (b)  Phase Two Premises:
               -------------------

               (i)    Landlord has heretofore delivered to Tenant for use of
          such plans and other information with respect to the Phase Two
          Premises and the Building as Tenant may reasonably require for the
          proper and expeditious preparation of Tenant's plans and
          specifications for the improvement of the Phase Two Premises.

               (ii)   Tenant shall cause its architect and M-E Engineering to
          prepare and, not later than February 6, 1998, shall deliver to
          Landlord complete construction drawings of Tenant's desired
          improvements to the Phase Two Premises signed and sealed by Tenant's
          architect including one mylar and two black line copies (which shall
          be 1/8" scale) together with a non-copyrighted CADD disc (collectively
          "Phase Two Premises Plans"). Landlord shall have until the expiration
          of six (6) business days after its receipt of the Phase Two Premises
          Plans to either approve such plans or to make reasonable modifications
          thereto, and the Phase Two Premises Plans shall be deemed modified to
          take account of any changes timely and reasonably required by
          Landlord.

               (iii)  Landlord shall, at its own cost and expense, in a good and
          workmanlike manner, cause the Phase Two Premises Plans to be improved
          and completed in accordance with the Phase Two Premise Plans (such
          work being herein called "Phase Two Landlord's Work"). Landlord
          reserves the right, however: [A] to make substitutions of material or
          components of equivalent grade and quality when and if any specified
          material or component shall not be readily or reasonably available,
          and, [B] to make changes necessitated by conditions met in the course
          of construction,

                                      30
<PAGE>

          provided that Tenant's approval of any substantial change shall first
          be obtained (which approval shall not be unreasonably withheld or
          delayed so long as there shall be general conformity with the
          substance and quality contemplated by the Phase Two Premises Plans).
          Landlord shall use reasonable efforts to cause the Phase Two Premises
          to be Ready for Occupancy on or before June 1, 1998 (the "Phase Two
          Scheduled Commencement Date").

               (iv)  If Landlord shall, for any reason (including, without
          limitation, failure to complete the Phase Two Landlord's Work) fail to
          make available to Tenant possession of the Phase Two Premises on or
          before the Phase Two Scheduled Commencement Date or any other date,
          Landlord shall not be subject to any liability for such failure nor
          for any failure to timely complete any work. Under such circumstances,
          Tenant's obligations to pay Base Rent, the Expense Adjustment Amount
          and Tax Adjustment Amount with respect to the Phase Two Premises shall
          not commence until the date the Phase Two Premises are Ready for
          Occupancy and such failure to cause the Phase Two Premises to be made
          Ready for Occupancy on or before the Phase Two Scheduled Commencement
          Date or any other date or to timely complete any work, shall not in
          any other way affect the validity or continuance of this Lease, nor
          the Term or the obligations of Tenant hereunder. Such deferral of rent
          shall be Tenant's sole and exclusive right and remedy with respect to
          any such failure. Notwithstanding the foregoing, there shall be no
          deferral of rent and Tenant, however, if any such failure is caused in
          whole or part by any act or omission of Tenant, its agents, servants,
          employees or contractors, which has the effect of hindering or
          delaying Landlord's delivery of possession or the timely completion of
          any work to be done by Landlord (hereinafter a "Phase Two Tenant
          Delay") including, without limitation, [A] any delay which is caused
          by Tenant's failure to deliver the Phase Two Premises Plans to
          Landlord on or before February 6, 1998, [B] any delay which is caused
          by changes in the work to be performed by Landlord in readying the
          Phase Two Premises for Tenant's occupancy, [C] any delay, not caused
          by Landlord, in furnishing materials or procuring labor required to be
          furnished or procured for the completion of the Phase Two Premises, or
          [D] any delay which is caused by any failure by Tenant, without regard
          to any grace period applicable thereto, promptly to furnish to
          Landlord any required information, approval or consent or caused by
          any good faith reluctance on the part of Landlord to approve any
          information required to be submitted by Tenant and approved by
          Landlord, or [E] any delay which is caused by the performance of any
          work or activity in the Phase Two Premises by Tenant or any of its
          employees, agents or contractors. Tenant also shall pay to Landlord,
          within 10 days after receipt of demand made from time to time
          (accompanied by documentation evidencing such costs and expenses), a
          sum equal to any reasonable additional costs and expenses incurred by
          Landlord in completing the Phase Two Premises resulting from any Phase
          Two Tenant Delay.

               (v)   Landlord shall provide an allowance (the "Phase Two
          Construction Allowance") for the payment of the costs and expenses of
          completing the Phase Two Landlord's Work in an amount up to Thirty-Two
          Thousand Eight Hundred Eighty-Six and No/100 Dollars ($32,886.00). The
          Phase Two Construction Allowance shall include but not be limited to
          all architectural and engineering fees, all costs of Phase Two
          Landlord's Work (from slab to slab), permit fees, Landlord supervision
          fee of 3% and contractor overhead costs. Tenant shall be responsible
          for the payment of all Phase Two Landlord's Work in excess of the
          Phase Two Construction Allowance (the "Excess Phase Two Tenant Costs")
          which excess shall be payable within thirty (30) days after Tenant's
          receipt of a written request from Landlord which request shall be
          accompanied by a calculation of the Phase Two Excess Tenant Costs in
          reasonable detail. If the cost of completing the Phase Two Landlord's
          Work is less than Phase Two Construction Allowance, the portion of the
          Phase Two Construction Allowance not used (the "Phase Two Construction
          Allowance Remainder") shall be paid, at Landlord's sole discretion, in
          one of the following manners: [A] the entire Phase Two Construction
          Allowance Remainder shall be paid directly to Tenant on or before the
          last day of the fifteenth (15th) month of the Term of the Lease, or
          [B] Tenant shall receive a credit upon the monthly Base Rent payable
          by Tenant in accordance with

                                      31
<PAGE>

          the provisions of Paragraph 2 in an amount equal to the quotient of
          the amount of the Phase Two Construction Allowance Remainder divided
          by sixty-six (66) (66 being the number of months in the Term).

     31.  Renewal Option.

          (a) Tenant shall have the option to renew ("Renewal Option") the term
     of the Lease for one (1) additional term of five (5) years ("Renewal Term")
     on the condition that Tenant is not in default under this Lease at the
     time Tenant gives notice of exercise of its renewal option or at the time
     of commencement of the renewal term.  Such renewal shall be on all of the
     terms, covenants and conditions of this Lease, except: (i) Tenant shall not
     have any right to further renewal beyond such additional five-year term;
     and (ii) the annual Base Rent for the Premises for the Renewal Term shall
     be the Fair Market Rental Rate ("FMRR") as defined in paragraph 31 (b)
     below; provided, however, in no event shall the Base Rent payable during
     the Renewal Term be less than $18.00 per square foot of rentable area
     comprising the Premises.  Tenant's Renewal Option shall be exercised only
     by Tenant giving Landlord six (6) months prior written notice of Tenant's
     election to renew, time being of the essence with respect to such notice.
     As of the date the Renewal Term begins, this Lease shall be deemed modified
     in the manner set forth above, without the necessity of any further
     agreement or document; provided, however, that either party to this Lease
     shall, upon request of the other party, execute, acknowledge, and deliver
     an instrument evidencing such renewal and modification of this Lease.

          (b)  Fair Market Rental Rate.
               ------------------------

               (i)    For the purposes of this Lease, the term "Fair Market
          Rental Rate" or "FMRR" shall mean an amount per square foot of the
          rentable area of the Premises per annum, reasonably determined by
          Landlord by reference to the market for comparable space (including
          the extent and condition of the build-out) in the Comparable
          Buildings, that a willing landlord would offer and a willing tenant
          would accept in an arms length transaction for the lease of such
          office space

                      [A]  commencing on the commencement date of the Renewal
               Term,

                      [B]  providing for no free rent, a tenant finish allowance
               equal to the value of the tenant improvements in place upon the
               Premises to a prospective tenant as of the commencement date of
               the Renewal Term, and

                      [C]  otherwise on all of the terms and conditions of this
               Lease, including the Tenant's obligation to pay the Expense
               Adjustment Amount and Tax Adjustment Amount in accordance with
               the provisions of Paragraph 4 using an Operating Expense Base
               Amount in the amount of $5.54 per rentable square foot per
               rentable and a Tax Base Amount of $ 1.11 per rentable square foot
               per annum.

               (ii)   Landlord shall deliver to Tenant its proposed FMRR for the
          Renewal Term within thirty (30) days after Landlord's receipt of
          notice of Tenant's election to exercise the Renewal Option ("Renewal
          Notice"). Landlord and Tenant shall use reasonable good faith efforts
          to mutually agree upon the FMRR within sixty (60) days after Tenant's
          delivery of the Renewal Notice.

               (iii)  In the event Landlord and Tenant cannot agree upon the
          FMRR for the Renewal Term within the sixty (60) days after Tenant's
          delivery of the Renewal Notice the FMRR shall be determined by
          appraisal, said appraisal shall be conducted in accordance with the
          following procedures:

                      [A]  Within twenty (20) days after receipt of a notice to
               appraise given by either party, Landlord and Tenant shall each
               select a real estate appraiser, who shall be a member of the
               American Institute of Real Estate Appraisers, and who shall have
               at least five (5) years appraisal experience with

                                       32
<PAGE>

               respect to commercial and office rental properties in the
               central business district of Denver, Colorado . If one of the
               parties hereto fails to appoint an appraiser within the time
               period prescribed, then the single appraiser appointed shall be
               the sole appraiser and shall determine the FMRR at issue. If two
               appraisers are appointed, they shall have thirty (30) days from
               the date the second appraiser is appointed (the "30-day Appraisal
               Period") within which to agree upon the FMMR at issue. The
               appraiser(s) shall be advised that the determination of the FMRR
               at issue shall be governed by the definitions of same set forth
               in this Lease. The determination by the two appraisers of the
               FMRR at issue shall be binding on Landlord and Tenant.

                      [B]  the two appraisers appointed by the parties hereto
               are unable to agree upon the FMRR at issue within the 30-day
               Appraisal Period, then said appraisers shall attempt within ten
               (10) days after the expiration of the 30-day Appraisal Period, to
               elect a third appraiser (the "Third Appraiser"). If the first two
               appraisers are unable to agree on the Third Appraiser within the
               ten (10) day period prescribed in the immediately preceding
               sentence, either Landlord or Tenant, by giving ten (10) days
               notice to the other party hereto, shall request that the
               presiding judge of the District Court for the City and County of
               Denver, State of Colorado select the Third Appraiser. The Third
               Appraiser, however, selected, shall meet the qualifications set
               forth in subparagraph 31 (b)(ii)[A] above, and shall be a person
               who has not previously acted in any capacity for either Landlord
               or Tenant.

                      [C]  On or before the tenth (10th) day after the Third
               Appraiser is appointed or selected, the first two appraisers
               shall each simultaneously submit in sealed envelopes his/her
               opinion of the fair market base rent at issue, together with any
               written arguments or data in support of said opinion(s), to the
               Third Appraiser. Within thirty (30) days after he/she is
               appointed or selected, the Third Appraiser shall determine the
               FMRR at issue by selecting one of the opinions submitted by the
               first two appraisers. The selection of the Third Appraiser shall
               be binding on Landlord and Tenant.

                      [D]  Each party hereto shall pay the fees and expenses of
               the appraiser selected by such party, and the fees and expenses
               of the Third Appraiser shall be borne equally by Landlord and
               Tenant.

     32.  Expansion Option.

          (a)  Landlord hereby grants Tenant an option (the "Expansion Option")
     to lease approximately 3,301 rentable square feet of office space (the
     "Expansion Space") located on the fifth (5/th/) floor of the Building, as
     reflected on Exhibit A-1 attached hereto and made a part hereof, subject to
                  -----------
     and upon the terms and provisions of this Paragraph 32.  Tenant shall
     exercise the Expansion Option if at all, prior to June 30, 1999, by giving
     Landlord written notice ("Expansion Notice") of exercise prior to June 30,
     1999.  If the Expansion Notice is not received by Landlord prior to June
     30, 1999, Tenant shall be deemed to have declined to exercise the Expansion
     Option and the Expansion Option shall be of no further force or effect.
     Tenant's Expansion Notice shall specify the date on which Tenant desires to
     occupy the Expansion Space which date shall not be less than one (1) month
     nor more than three (3) months from the date of Tenant's notice.  If no
     date is specified in the Expansion Notice, it shall be deemed that Tenant
     desires to occupy the Expansion Space at the earliest date possible.
     Notwithstanding the forgoing, the Tenant shall have no right to exercise
     the Expansion Option if Tenant is in default under this Lease (after the
     expiration of any applicable cure period) at any time when it attempts to
     exercise the Expansion Option or at any time thereafter until the Expansion
     Space has been added to the Premises.

          (b)  Upon the notice referred to in paragraph 32(a) above being given
     and within such time as Landlord reasonably determines is necessary to
     complete the Expansion Space for occupancy by no later than the date
     specified in Tenant's notice of exercise, Landlord

                                       33
<PAGE>

     shall cause the Expansion Space to be improved and completed in a manner
     comparable to the original completion of the initial Premises (the
     "Landlord's Expansion Space Work").

          (c)  Landlord shall provide an allowance (the "Expansion Space
     Construction Allowance") for the payment of the costs and expenses of
     completing the Landlord's Expansion Space Work in an amount up to Sixty
     Thousand Six Hundred Eighteen and No/100 Dollars ($60,618.00).  The
     Expansion Space Construction Allowance shall include but not be limited to
     all architectural and engineering fees, all costs of Landlord's Expansion
     Space Work (from slab to slab), permit fees, Landlord supervision fee of 3%
     and contractor overhead costs.  Tenant shall be responsible for the payment
     of all Landlord's Expansion Space Work in excess of the Expansion Space
     Construction Allowance (the "Excess Expansion Space Tenant Costs") which
     excess shall be payable within thirty (30) days after Tenant's receipt of a
     written request from Landlord which request shall be accompanied by a
     calculation of the Excess Expansion Space Tenant Costs in reasonable
     detail.  If the cost of completing the Landlord's Expansion Space Work is
     less than Expansion Space Construction Allowance, the portion of the
     Expansion Space Construction Allowance not used shall be paid by Landlord
     to Tenant on or before the later of the (i) last day of the fifteenth
     (15/th/) month of the Term of the Lease, and (ii) the ninetieth (90th) day
     after the Expansion Space has been added to the Premises.

          (d)  The Expansion Space shall be added to the Premises, for all
     purposes, as of the date such space is completed for Tenant's occupancy,
     but not earlier than the date, if any, specified in the Expansion Notice as
     the date the Expansion Space is ready for Tenant's occupancy, for the
     balance of the Term of this Lease and subject to and upon the following
     economic terms and all of the other terms, covenants and conditions of this
     Lease, provided that the Base Rent for the Expansion Space shall be as
     follows:

                                             Base Rent Per Square
          Period                             Foot of Rentable Area
          ------                             ---------------------

          For Months 1-24 of the Term:       $52,815.96 per annum/$4,401.33 per
                                             month (based on $16.00 per square
                                             foot of rentable area per annum)

          For Months 25-36 of the Term:      $56,117.04 per annum/$4,676.42 per
                                             month (based on $17.00 per square
                                             foot of rentable area per annum)

          For Months 37-66 of the Term:      $59,418.00 per annum/$4,951.50 per
                                             month (based on $18.00 per square
                                             foot of rentable area per annum)

     The annual Base Rent shall be payable in equal monthly installments, in
     advance, on the first day of each month, without any demand or setoff.
     Tenant's Proportionate Share shall be increased to 2.254% calculated by
     dividing 11,565 square feet, the rentable area of the Premises (including
     the Expansion Space), by 512,995 square feet. Upon addition of the
     Expansion Space to the Premises, this Lease shall be deemed modified in the
     manner set forth above without the necessity of any further agreement or
     document; provided, however, that either party shall, upon request of the
     other party, execute, acknowledge and deliver an instrument evidencing such
     modification of this Lease.

     33.  Right of First Offer.  Upon and subject to all the terms and
conditions set forth in this Paragraph 33, Landlord hereby grants to Tenant is a
right of first offer (the "Right of First Offer") pertaining to the office space
located upon the fifth (5th) floor of the Building which is not part of the
original Premises, the Expansion Space and which may become available from time
to time for lease during the Term of the Lease (the "Offer Space").  The Right
of First Offer shall be on the following terms and conditions:

          (a)  If Landlord shall desire to lease all or any portion of the Offer
     Space, as evidenced by the initiation of formal negotiations with or the
     issuance of a proposal to a third

                                       34
<PAGE>

     party by or on behalf of Landlord covering any portion of the Offer Space,
     or Landlord's acceptance of a proposal from a third party, Landlord shall
     first offer to lease such part of the Offer Space (the "Designated Offer
     Space") to Tenant, by giving written notice to Tenant. Such notice shall
     specify the date on which the Designated Offer Space is expected to be
     available for Tenant's lease (the "Scheduled Designated Offer Space
     Commencement Date"). Within five (5) business days after Landlord gives
     Tenant such notice, Tenant shall, by written notice to Landlord (the "Offer
     Notice"), elect or decline to exercise its Right of First Offer. If Tenant
     fails to deliver the Offer Notice to Landlord within such period of five
     (5) business days, Tenant shall be deemed to have declined to exercise its
     Right of First Offer. If Tenant declines or is deemed to have declined to
     exercise its Right of First Offer, Landlord thereafter shall have the right
     to lease such Designated Offer Space to any party upon such terms and
     conditions and for such period or successive period of time as Landlord, in
     its sole discretion, shall determine. Notwithstanding the foregoing, Tenant
     shall have no right to exercise the Right of First Offer (and, at
     Landlord's option, any previous exercise of the Right of First Offer shall
     be null and void) if at the time Tenant first attempts to exercise the
     Right of First Offer, or at any time thereafter until the Designated Offer
     Space has been added to the Premises, Tenant is in default under this
     Lease.

          (b)  In the event Tenant exercises the Right of First Offer, Tenant
     shall deliver to Landlord the Tenant's proposed layout plans and
     specifications for such Designated Offer Space within ten (10) business
     days after delivery of the Offer Notice.  Upon the Offer Notice being given
     and within such time as Landlord reasonably determines is necessary to
     complete such Designated Offer Space for occupancy, Landlord shall cause
     such Designated Offer Space to be improved and completed in a manner
     consistent with the Tenant's layout plans and specifications for such
     Designated Offer Space (the "Designated Offer Space Improvements").  The
     "Commencement Date" with respect to the Designated Offer Space ("Designated
     Offer Space Commencement Date") shall be deemed to be that date which is
     the later of the Scheduled Designated Offer Space Commencement Date or the
     first business day after the substantial completion of the Designated Offer
     Space Improvements.

          (c)  The Designated Offer Space shall be added to the Premises, for
     all purposes, as of the Designated Offer Space Commencement Date for the
     balance of the Term of this Lease and subject to and upon the following
     economic terms and all of the other terms, covenants and conditions of this
     Lease, except that:

               (i)   the annual Base Rent for the Designated Offer Space shall
          be at the prevailing market rates for office space in the Building
          comparable to the Designated Offer Space at the time of the Designated
          Offer Space Commencement Date; provided, however, in no event shall
          the Base Rent for the Designated Offer Space be less than the Base
          Rent provided for the Expansion Space in paragraph 32(c) above on a
          per square foot of rentable area basis.

               (ii)  Tenant's Proportionate Share shall be increased to a new
          percentage, calculated in accordance with the provisions of Paragraph
          4 above by increasing the rentable area of the Premises by the number
          of square feet comprising the rentable area of the Designated Offer
          Space. Tenant's obligation to pay Base Rent, Expense Adjustment Amount
          and Tax Adjustment Amounts for the Designated Offer Space shall
          commence on the Designated Offer Space Commencement Date. Upon
          addition of the Designated Offer Space to the Premises, the Lease
          shall be deemed modified in the manner set forth above without the
          necessity of any further agreement or document; provided, however,
          Landlord and Tenant agree to execute, acknowledge and deliver an
          instrument evidencing such modification of the Lease to be prepared by
          Landlord.

     34.  Parking.  Tenant shall have the right to rent up to ten (10) parking
spaces in accordance with the provisions of Exhibit D attached hereto and
                                            ---------
incorporated herein by this reference.

                                       35
<PAGE>

    All of the terms and provisions of the Lease, as herein amended and
supplemented, are hereby ratified and confirmed, and shall remain in full force
and effect.

    IN WITNESS WHEREOF, the parties hereto have caused this Addendum to be duly
executed as of the day and year first above written.

                                    LANDLORD:

                                    DENVER-STELLAR ASSOCIATES
                                    LIMITED PARTNERSHIP, a Delaware
                                    limited partnership

                                    By: Amerimar Realty Management Co.-
                                        Colorado

                                        By: Amerimar Realty Management-
                                            Pennsylvania, its general partner

                                    By: /s/ David G. Marshall
                                       -----------------------------------------
                                        David G. Marshall, President

                                    TENANT:

                                    PRIME RESPONSE, INC., a Delaware
                                    corporation

                                    By: /s/ Robert Fetter CEO
                                       -----------------------------------------
                                              Authorized Signature (Title)

                                      36
<PAGE>

                                   EXHIBIT B
                                   ---------

                             RULES AND REGULATIONS

     Rules and Regulations, to Lease between DENVER-STELLAR ASSOCIATES LIMITED
PARTNERSHIP, a Delaware limited partnership, as Landlord ("Landlord") and PRIME
RESPONSE, INC., a Delaware corporation as tenant ("Tenant"), pertaining to
certain space in Denver Place Plaza Tower, 1099 18th Street, Denver, Colorado
80202.

          (a)  Any sign, lettering, picture, notice, or advertisement installed
     within Tenant's Premises which is visible to the public from within the
     Building shall be installed at Tenant's cost and in such manner, character
     and style as Landlord may approve in writing.  No sign, lettering, picture,
     notice or advertisement shall be placed on any outside window or in any
     position so as to be visible from outside the Building.

          (b)  The use of the name of the Building or of pictures or
     illustrations of the Building in advertising or other publicity, without
     prior written consent of Landlord, is prohibited.

          (c)  Tenant, its subtenants and its and their customers, invitees,
     licensees, and guests

               (i)   shall not obstruct and shall not use for any purpose other
          than ingress and egress, the sidewalks, entrances, passages, courts,
          corridors, vestibules, halls, elevators and stairways in and about the
          Building;

               (ii)  shall not place objects against glass partitions or doors
          or windows or adjacent to any open common space which would be
          unsightly from the Building corridors or from the exterior of the
          Building, and will promptly remove the same upon notice from Landlord;

               (iii) shall not make noises, cause disturbances, create
          vibrations, odors or noxious fumes or use or operate any electrical or
          electronic devices or other devices that emit sound waves or are
          dangerous to other tenants and occupants of the Building or that would
          interfere with the operation of any device or equipment or radio or
          television broadcasting or reception from or within the Building or
          elsewhere, and shall not place or install any projections, antennae,
          aerials or similar devices inside or outside of the Premises;

               (iv)  shall not make any room-to-room canvass to solicit business
          from other tenants in the Building, and shall not exhibit, sell or
          offer to sell, use, rent or exchange any item or services in or from
          the Premises unless ordinarily embraced within the Tenant's use of the
          Premises as specified in its lease;

               (v)   shall refrain from attempting to adjust any controls;

               (vi)  shall not waste, and shall not suffer or permit to be
          wasted, electricity or water and shall cooperate fully with Landlord
          to assure the most effective operation of the Building's heating and
          air conditioning;

               (vii)  shall keep public corridor doors closed;

               (viii) shall neither install nor operate machinery or any
          mechanical devices of a nature not directly related to Tenant's
          ordinary use of the Premises without the written permission of the
          Landlord;

               (ix)   shall not use rest rooms or water fixtures for any purpose
          other than that for which they are designed;

                                      37
<PAGE>

               (x)   shall not mark upon, paint, cut, drill into, drive nails or
          screws into, or in any way deface the walls, ceiling partitions
          or floors of the leased Premises or of the Building;

               (xi)  shall not unduly obstruct any pipes, conduits and ducts in
          the Premises; and

               (xii) shall use chair pads, to be furnished by Tenant, under all
          rolling and ordinary desk chairs in the carpeted areas.

          (d)  Tenant assumes full responsibility for protecting its space from
     theft, robbery and pilferage, which includes keeping doors locked and other
     means of entry to the Premises closed and secured.

          (e)  Peddlers, solicitors and beggars shall be reported to the office
     of the Building or as Landlord otherwise requests.

          (f)  No person or contractor not employed by Landlord shall be used to
     perform window washing, cleaning, or other work in the Premises.

          (g)  Unless Landlord so consents, Tenant shall not, and Tenant shall.
     not permit or suffer anyone to:

               (i)   Cook in the premises;

               (ii)  Place vending or dispensing machines of any kind in the
          Premises; or

               (iii) At any time sell, purchase or give away, or permit the
          sale, purchase or gift of, food in any form.

               (iv)  Use the Premises for lodging or for any immoral or illegal
          purposes.

               (v)   Use the Premises to engage in the manufacture or sale of,
          or permit the use of, any spirituous, fermented, intoxicating or
          alcoholic beverages on the Premises.

               (vi)  Use the Premises to engage in the manufacture or sale of,
          or permit the use of, any illegal drugs.

          (h) No furniture shall be placed in front of the building or in any
     lobby or corridor, without the prior written consent of Landlord.  Landlord
     shall have the right to remove all non-permitted signs and furniture,
     without notice to Tenant, at Tenant's expense.

          (i) No animals are allowed in the Building.

          (j) No lock or other security device shall be placed by Tenant on any
     door in the Building without the Building manager being kept furnished with
     two of the keys, cards or other means of access therefore.  At the
     termination of its tenancy, Tenant shall promptly deliver to Landlord all
     keys, entry cards and other means of access to offices, rest rooms and
     vaults.

          (k) The use of oil, gas or inflammable liquids for heating, lighting,
     or any other purpose is expressly prohibited.  Explosives or other
     hazardous articles shall not be brought into the Building.

          (l) Electric floor space heaters, humidifiers or A/C fans are not
     permitted.

          (m) Landlord shall have the right to approve or disapprove the movers
     or moving company employed by Tenant.  Tenant shall cause said movers to
     use only the loading facilities and elevator designated by Landlord.  In
     the event Tenant's movers damage the elevator or any part of the Building,
     Tenant shall forthwith pay to Landlord the amount required to repair said
     damage.

                                      38
<PAGE>

          (n) If any Tenant desires telegraphic, telephonic, computer or other
     electric connections, Landlord, or its agents, will direct the electricians
     as to where and how the wires may be introduced, and without such
     directions, no boring or cutting for wires will be permitted.  Any such
     installation and connection shall be made at Tenant's expenses, and, at
     Landlord's option, shall be removed at Tenant's expense at the expiration
     or termination of its Lease.

          (o) Except for the following smoking areas specifically designated by
     Landlord, the outdoor Plaza level of 1099 - 18th Street, the outdoor areas
     at the corner of 18th and Champa and 19th and Curtis and the Smoke Haus in
     the mall, all common areas of the building, including all sidewalks,
     entries, passages, stairways, elevators, restrooms, lobbies and hallways,
     shall be non-smoking areas.  Tenant shall be responsible to prevent its
     employees, agents, visitors, customers and guests from smoking in such
     common areas.

          (p) During the normal office hours of 6:00 a.m. to 6:00 p.m., Monday
     through Friday, Tenant and its employees and agents shall observe the
     building dress code, which requires a neat and clean appearance and
     prohibits the wearing of cutoffs and ragged, torn, ripped, rent or holey
     apparel.

          (q) The Landlord reserves the right to modify and make such other and
     further reasonable rules and regulations as in its judgment may, from time
     to time, be needful and desirable for the safety, security, care and
     cleanliness of the Premises and preservation of good order and therein.

                                      39
<PAGE>

                                   EXHIBIT C
                                   ---------

                             LEASE TERM AGREEMENT

     THIS AGREEMENT, made as of the 20th day of January, 1998, between DENVER-
STELLAR ASSOCIATES LIMITED PARTNERSHIP, a Delaware limited partnership
(hereinafter referred to as "Landlord") and PRIME RESPONSE, INC., a Delaware
corporation (hereinafter referred to as "Tenant").

                                  WITNESSETH

     WHEREAS, by Lease (hereinafter called "Lease") made as of the 20th day of
January, 1 1998, Landlord leased unto Tenant certain premises known as Suite
Number 500, located at 1099 Eighteenth Street, Denver, Colorado, for a term of
five (5) years, three (3) months and zero (0) days commencing on June 1, 1998,
unless sooner terminated or extended as provided therein, and

     WHEREAS, Landlord and Tenant now desire to set forth the correct
Commencement Date of the term and to adjust the Expiration Date of the Term to
provide for a full term of the Lease of _________ years, _______ months and
_________ days.

     NOW, THEREFORE, Landlord and Tenant do hereby agree as follows:

     1. The Term of the Lease commenced __________ 1998, and shall continue
        until _____________, 2002 unless sooner terminated or extended as
        provided therein.

     2. Except as hereby amended, the Lease shall continue in full force and
        effect.

     3. This Agreement shall be binding on the parties hereto, their heirs,
        executors, successors and assigns.

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed as of the day and year first above written.

                                    LANDLORD:

                                    DENVER-STELLAR ASSOCIATES
                                    LIMITED PARTNERSHIP, a Delaware
                                    limited partnership

                                    By:  Amerimar Realty Management Co.-
                                         Colorado

                                         By:   Amerimar Realty Management-
                                               Pennsylvania, its general partner

                                               By:  ARC-Management
                                                    Company, its general
                                                    partner

                                         By: /s/ David G. Marshall
                                            ------------------------------------
                                             David G. Marshall, President

                                         TENANT:

                                         PRIME RESPONSE, INC., a Delaware
                                         corporation

                                         By: /s/ Robert Fetter CEO
                                            ------------------------------------
                                                    Authorized Signature (Title)

                                      40
<PAGE>

                                   EXHIBIT D
                                   ---------

                               PARKING AGREEMENT

          DENVER-STELLAR ASSOCIATES LIMITED PARTNERSHIP, a Delaware limited
partnership a Landlord, and PRIME RESPONSE, INC., a Delaware corporation, as
Tenant, have executed simultaneously with this Agreement a Lease (hereinafter
called "Lease") pertaining to certain space at 1099 Eighteenth Street to be
occupied by Tenant. In consideration of die mutual covenants herein contained,
Landlord and Tenant further agree as follows:

          The Building in which the Premises are located contains a parking
garage for the benefit of Tenants and the general public (hereinafter called
"Parking Garage"), and Landlord's affiliate owns that commercial office complex
known as Denver Place located at 999 - 18th Street which contains a parking
garage for the benefit of tenants and the general public (the "Complex Parking
Garage"). Landlord and its affiliates do not operate or manage the Parking
Garage and Complex Parking Garage, respectively, but maintain a management
agreement with an independent contractor (hereinafter called "Operator") for the
management and operation of the Parking Garage and Complex Parking Garage. In
order to rent parking spaces in the Parking Garage or Complex Parking Garage,
Tenant must contract separately with the Operator for such rentals. Landlord
shall make available for Tenant and Tenant shall have a non-assignable option to
rent from the Operator up to ten (10) unreserved parking spaces located, at
Landlord's election, in either the Parking Garage or Complex Parking Garage
beginning April 1, 1998 at the monthly rates announced from time to time
throughout the Term of the Lease by the Operator. Tenant must exercise its
option to take such parking spaces by delivery of not less than thirty (30)
days' prior written notice to Landlord on or before May 31, 1998 or Tenant's
right to lease the parking spaces will expire. In the event Tenant does not
exercise its Expansion Option in accordance with Paragraph 32 of the Lease,
Landlord shall have die option to terminate Tenant's right to lease four (4) of
the ten (10) parking spaces at any time thereafter upon thirty (30) days'
written notice to Tenant.

          The terms and conditions of Tenant's rental shall be governed and
fixed solely by the rental agreement between Tenant and Operator, however,
Tenant's failure to comply with any term of any such rental agreement shall
constitute a default under the Lease. In the event that Tenant chooses to rent
parking spaces from the Operator as provided for herein, Tenant shall be
responsible for payment to the Operator of a refundable security deposit for
each parking card issued by the Operator in connection with Tenant's rental of
the parking spaces (the "Security Deposit"). The Security Deposit shall be in an
amount to be determined by the Operator in its sole discretion. Notwithstanding
anything in this Agreement or the Lease to the contrary, in no event shall
Landlord be responsible for payment of the Security Deposit to the Operator on
behalf of Tenant. Payment and refund of the Security Deposit shall be governed
and fixed solely by the rental agreement between Tenant and Operator. Landlord's
holding of parking spaces shall not constitute any assumption of and Tenant
hereby releases Landlord from any and all liability with respect to such
rentals, and any and all damage, loss or injury with respect to such rentals
shall be at the sole risk of Tenant unless otherwise provided by Operator under
the rental agreement.

          The provisions of this Agreement supplement but are subject to all
provisions of the Lease. Capitalized terms not otherwise defined in this
Agreement have the same meaning as the same terms have in the Lease.

                         LANDLORD:

                         DENVER-STELLAR ASSOCIATES LIMITED
                         PARTNERSHIP, a Delaware limited partnership

                         By:  Amerimar Realty Management Co.- Colorado

                              By:   Amerimar Realty Management-
                                    Pennsylvania, its general partner

                                    By:  ARC-Management Company,
                                         its general partner

                         By: /s/ David G. Marshall
                            -----------------------------------------
                              David G. Marshall, President

                         TENANT:

                         PRIME RESPONSE, INC., a Delaware corporation

                         By: /s/ Robert Fetter CEO
                            ----------------------------------------

                                      41

<PAGE>

                                   EXHIBIT E
                                   ---------

                                  WORKLETTER

1.   Tenant Inspection. Tenant shall be permitted to designate a representative
     -----------------
     to make periodic inspections of the Premise during construction during
     reasonable business hours, provided such representative is accompanied by a
     representative of Landlord which representative shall be reasonably
     available to accompany Tenant's representative.

2.   Acceptance of Premises. Upon the Substantial Completion (as hereinafter
     ----------------------
     defined) of the Landlord's Work, Tenant, Landlord, Landlord's architect and
     Landlord's contractor shall make an inspection of the Premises to determine
     that the construction and installation of the Landlord's Work has been
     completed in accordance with Filial Layout Plans and to prepare a "Punch
     List" of work requiring correction or completion by Landlord. Subject to
     Unavoidable Delays, Landlord shall correct or complete all "Punch List"
     items within sixty (60) days after the inspection. The term "Unavoidable
     Delays" means delays caused by strikes, acts of God, lockouts, riots,
     explosions, sabotage accident governmental restrictions, enemy action,
     civil commotion, fire or other casualty or similar causes beyond the
     reasonable control of Landlord.

3.   Access. It is understood that Landlord and Landlord's contractors will
     ------
     cooperate with Tenant's cabling, phone and moving contractors and other
     vendors, including early access before the Commencement Date as long as
     such access does not interfere with the completion of Landlord's Work.

4.   Substantial Completion. Substantial Completion shall mean (i) except for
     ----------------------
     minor items which shall not prevent Tenant from making use of the Premises
     as described under the terms of the Lease, the Premises have been improved
     by Landlord in substantial conformity with the Filial Layout Plans, (ii)
     any remaining work to be finished as identified in the Punch List can be
     completed without significant interference to the conduct of Tenant's
     business in the Premises, and (iii) all necessary governmental approvals
     and permits required for Tenant's occupancy of the Premises have been
     obtained.

                                      42

<PAGE>

                            COMMENCEMENT AGREEMENT
                                EXPANSION SPACE

     THIS AGREEMENT, made of the 15th day of October, 1998, between Amerimar
Realty Management Co.-Colorado, as agent for DENVER-STELLAR ASSOCIATES LIMITED
PARTNERSHIP, a Delaware limited partnership (hereinafter referred to as
"Landlord") and PRIME RESPONSE, INC., (hereinafter referred to as "Tenant") now
desire to set forth the correct Commencement Date for the 3,301 rentable square
feet of expansion space as follows:

     The Term for the 30,301 rentable square feet commenced on September 24,
     1998, and shall continue until December 31, 2003, unless sooner terminated
     or extended as provided for in the Lease.

Please indicate your acceptance of this agreement by signing two copies of the
Commencement Agreement and returning them to Landlord.

                              TENANT:

                              PRIME RESPONSE, INC.

                              By: /s/ Cathy Lewis
                                 -----------------------------------------
                                      Cathy Lewis
Date; 10/21/98                        Vice President of Finance
     -----------------------
<PAGE>

                           FIRST AMENDMENT TO LEASE

          THIS FIRST AMENDMENT TO LEASE ("First Amendment") is made and entered
into this 22/nd/ day of June, 1998, by and between DENVER-STELLAR ASSOCIATES
LIMITED PARTNERSHIP, a Delaware limited partnership (hereinafter called
"Landlord") and PRIME RESPONSE, INC. a Delaware corporation, (hereinafter called
"Tenant").

                                R E C I T A L S

     A.   Landlord and Tenant entered into that certain Denver Place Office
Lease dated January 20, 1998 (the "Original Lease"), pursuant to which Tenant
leased approximately 8,264 square feet of rentable area on the fifth (5/th/) for
(the "Original Premises'), known as Suite 500, of the office building known as
Denver Place Plaza Tower, located at 1099 18th Street, Denver, Colorado (the
"Building").

     B.   Tenant has requested and Landlord has agreed to lease to Tenant an
additional 3,301 rentable square feet of area on the fifth (5/th/) floor of the
Building.

     C.   Landlord and Tenant are the sole parties in interest under the Lease.

     D.   Landlord and Tenant now desire to amend the Lease in the manner and
form set forth herein.

                               A G R E E M E N T

     NOW, THEREFORE, for good and valuable consideration, receipt of which is
hereby acknowledged, Landlord and Tenant hereby amend the Lease as follows:

     1.   First Added Premises. Effective September 1, 1998, or the date upon
which the Landlord notifies the Tenant that the expansion space (defined below)
is ready for occupancy, whichever first occurs (the "First Added Premises
Commencement Date") that certain space on the 5th floor of the Plaza Tower of
the Building, containing approximately 3,301 square feet of rentable area and
designated as the first added premises (the "First Added Premises"), as shown on
the floor plan attached as Exhibit A-1, shall be added to the Premises for the
                           -----------
balance of the Term, upon and subject to all of the terms, covenants and
conditions of the Lease, except as outlined in this First Amendment. Landlord
and Tenant agree that the area of the Original Premises and First Added Premises
is 11,565 rentable square feet.

     2.   Rent. Effective the First Added Premises Commencement Date, Tenant
shall pay to Landlord the following Base Rent:

     (a)  From July 1, 1998 through First Added Premises Commencement Date:

          Original Premises:        $132,224.04 per annum/$11,018.67 per month

     (b)  From First Added Premises Commencement Date through June 30, 2000:

          Original Premises:        $132,224.04 per annum/$11,018.67 per month
          First Added Premises:     $52,815.96 per annum/$4,401.33 per month
<PAGE>

     (c)  From July 1, 2000 through June 30, 2001:

          Original Premises:        $140,487.36 per annum/$11,707.28 per month
          First Added Premises:     $56,117.04 per annum/$4,676.42 per month

     (d)  From July 1, 2001 through December 31, 2003:

          Original Premises:        $148,752.00 per annum/$12,396.00 per month
          First Added Premises:     $59,418.00 per annum/$4,951.50 per month

     3.   Additional Rent. In addition to paying the Base Rent specified in
Paragraph 2 above, from the First Added Premises Commencement Date through and
including the Expiration Date, Tenant shall pay as additional rent the amounts
determined in accordance with the provisions of Paragraph 4 of the Lease,
provided that Tenant's Proportionate Share shall be 2.25% (being the percentage
calculated by dividing 11,565 square feet, the rentable are of the Original
Premises and the First Added Premises, by 512,995 being 95% of the rentable area
of the Building). The Base Rent and additional rent are sometimes herein
collectively referred to as the "rent". all amounts of additional rent shall by
payable in the same manner and at the same place as the Base Rent.

     4.   Improvements of First Added Premises.

          (a)  Landlord shall deliver to Tenant for use by Tenant and Tenant's
     architect, such plan or plans and other information with respect to the
     First Added Premises and the Building as Tenant may reasonably require for
     proper and expeditious preparation of Tenant's layout plans. Landlord shall
     upon reasonable prior request by Tenant, allow access to the First Added
     Premises for Tenant and Tenant's architect as reasonably necessary in
     connection with the preparation of such plans.

          (b)  Tenant shall, at Tenant's expense, cause to be prepared not later
     than July 6, 1998, and delivered to Landlord, one conceptual space plan
     ("Tenant's Conceptual Space Plan") prepared by an architect, approved by
     Landlord, ("Tenant's Architect") which approval shall not be unreasonably
     withheld or delayed, for the construction and finishing of the First Added
     Premises for Tenant's occupancy. Tenant's Conceptual Space Plan, when
     finalized, shall be signed and sealed by Tenant's Architect and shall
     conform to all applicable laws and requirements of public authorities.
     Tenant's Conceptual Space Plan shall be subject to Landlord's review and
     written approval, which approval shall not be unreasonably withheld, and
     Tenant shall modify such plans to take account of any changes reasonably
     required by Landlord. Landlord shall complete such review and respond to
     Tenant within ten (10) business days after Landlord's receipt of such
     Conceptual Space Plan. Unless Landlord shall have notified Tenant in
     writing to the contrary within such 10-business day period stating
     specifically any disapprovals, Tenant's Conceptual Space Plan shall be
     deemed to have been approved by Landlord. Tenant's Conceptual Space Plan as
     approved by Landlord and with the aforesaid modifications, if any, are
     herein called the "First Added Premises Space Plans" with specifications
     which shall be provided to Landlord in a hard copy and in electronic format
     within seven (7) days of Landlord's approval. Concurrently with the
     delivery of Tenant's First Added Premises Space Plans to Landlord, Landlord
     and Tenant shall by notice to the other in writing designate a single
     individual who shall be available to meet and consult at the Premises as
     Landlord's and Tenant's representatives respecting the matters which are
     the subject of this Paragraph 4 and who, as between Landlord and Tenant,
     shall have the power to make day-to-day decisions on this construction
     project.

          (c)  Landlord, at Tenant's sole cost and expense, shall have its
     engineers prepare and not later than fifteen (15) business days after
     Landlord's receipt of the First Added Premises Space Plans, shall deliver
     to Tenant mechanical, electrical and fire protection engineering drawings
     and specifications ("First Added Premises Engineering Plans"), based on the
     First Added Premises Space Plans (and such pertinent additional information
     as shall have been submitted by Tenant or requested by Landlord), as may be
     required to

                                       2
<PAGE>

     complete the First Added Premises in accordance with the First Added
     Premises Space Plans. Within six (6) business days after submission to
     Tenant by Landlord of the First Added Premises Engineering Plans, Tenant
     shall give its written approval thereof if they are a direct extension of
     the First Added Premises Space Plans, otherwise such approval shall not be
     unreasonably withheld, and Tenant must submit any reasonable modifications
     to such plans within this same time period; however, the First Added
     Premises Engineering Plans shall be deemed to have been approved by Tenant
     unless Tenant shall have notified Landlord in writing to the contrary
     within six (6) business days of their receipt by Tenant, stating in which
     respects such plans fail to conform with the First Added Premises Space
     Plans. The First Added Premises Engineering Plans shall be deemed to have
     been approved by Tenant if they are returned by Tenant with specified
     changes noted and such changes are made, whether or not approval is
     thereafter specifically noted on the First Added Premises Engineering Plans
     so changed.

          (d)  Landlord shall at Tenant's own cost and expense less the
     "Construction Allowance" described in paragraph 4(f) hereof, cause the
     First Added Premises to be improved and completed in accordance with the
     First Added Premises Space Plans and First Added Premises Engineering Plans
     ("Construction Drawings"). Landlord reserves the right, however, (i) to
     make substitutions of material or components of equivalent grade and
     quality when and if any specified material or component shall not be
     readily or reasonably available, and (ii) to make changes necessitated by
     conditions met in the course of construction; provided, however that in all
     such instances of substitutions or changes Tenant's approval of any change
     shall first be obtained (which approval shall not be unreasonably withheld
     or delayed so long as there shall be general conformity with the
     Construction Drawings and the budget which had been previously approved by
     Tenant).

          (e)  If Landlord shall, for any reason (including, without limitation,
     failure to complete the work, if any, required to be done by Landlord under
     this lease) fail to make available to Tenant possession of the First Added
     Premises on or before September 1, 1998, or any other date, Landlord shall
     not be subject to any liability for such failure nor for any failure to
     timely complete any work. Under such circumstances, Tenant's obligations to
     pay Base Rent and Tenant's Share of Operating Expenses with respect to the
     First Added Premises shall not commence until Landlord makes possession
     available; and such failure to make available to Tenant possession of the
     First Added Premises on the September 1, 1998 or any other date or to
     timely complete any work, shall not in any other way affect the validity or
     continuance of this First Amendment, nor the Term or the obligations of
     Tenant hereunder. Such deferral of rent shall be Tenant's sole and
     exclusive right and remedy with respect to any such failure. There shall be
     no deferral of rent, however, if such failure is caused in whole or part by
     any act or omission of Tenant, its agents, servants, employees or
     contractors, which has the effect of hindering or delaying Landlord's
     delivery of possession or the timely completion of any work to be done by
     Landlord (hereinafter a "Tenant Delay") which Tenant Delays are defined as:
     (a) any delay which is caused by changes made by Tenant (other than as may
     be subsequently required by any inspecting agency or for existing
     conditions which were not evident on Landlord's original plans) in the work
     to be performed by Landlord in readying the First Added Premises for
     Tenant's occupancy, (b) any delay which is caused by any failure by Tenant,
     without regard to any grace period applicable thereto, promptly to furnish
     to Landlord any required information, approval or consent or caused by any
     good faith reluctance on the part of Landlord to approve any information
     required to be submitted by Tenant and approved by Landlord, or (c) any
     delay which is caused by the performance of any work or activity in the
     First Added Premises by Tenant or any of its employees, agents or
     contractors. Tenant shall also pay to Landlord, within 10 days after
     receipt of demand made from time to time, a sum equal to any additional
     cost to Landlord in completing the First Added Premises resulting from any
     Tenant Delay. Tenant may, upon agreement with the general contractor
     performing such work, schedule Tenant's phone and cable contractor to
     install Tenant's telephone, cabling and ancillary equipment at a mutually
     agreeable time.

                                       3
<PAGE>

          (f)  Landlord shall provide an allowance (the "Construction
     Allowance") for the payment of the costs and expenses of completing the
     Landlord's First Added Premises Work in an amount of Sixty Thousand Six
     Hundred Eighteen and no/100 Dollars ($60,618.00). Tenant shall be
     responsible for the payment of all Landlord's First Added Premises Work in
     excess of the Construction Allowance (the "Excess Tenant Costs") which
     excess shall be payable within thirty (30) days after Tenant's receipt of a
     written request from Landlord which request shall be accompanied by a
     calculation of the Excess Tenant Costs in reasonable detail. If the cost of
     completing the Landlord's First Added Premises Work is less than
     Construction Allowance, the portion of the Construction Allowance not used
     shall be paid directly to Tenant on or before the later of the (i) last day
     of the fifteenth (15/th/) month of the Term of the Lease, and (ii) the
     ninetieth (90/th/) day after the First Added Premises has been added to the
     Original Premises.

     5.   Parking. Beginning July 1, 1997, Exhibit "D" attached to the Original
lease (the "Parking Agreement') shall be amended to reflect that Landlord shall
reserve for Tenant an option to lease one (1) "reserved" and up to two (2)
"unreserved" parking spaces in the Parking Garage. The parking spaces shall be
provided at the monthly rates announced from time to time by the operator of the
Parking Garage. Tenant's failure to pay any rent due pertaining to any such
parking spaces shall constitute an event of default under the Lease as herein
amended.

     6.   Security Deposit. Tenant shall pay to Landlord the sum of Four
Thousand Four Hundred One and 33/100 Dollars ($4,401.33) to be held as
additional security deposit in accordance with paragraph 24 of the Original
Lease, which shall be paid to Landlord with the execution of this First
Amendment by Tenant.

     7.   Termination of Expansion Option. The Tenant's Expansion Option
provided in paragraph 32 of the Original Lease is terminated and null, void and
of no further effect.

     8.   Binding Effect. This First Amendment becomes effective only upon the
execution by Landlord and Tenant.

     9.   Conflict. If there is any conflict between the terms and provisions of
this First Amendment and the terms and provisions of the Lease, the terms and
provisions of this First Amendment shall govern. Except as herein specifically
set forth, all of the provisions of the Lease shall remain in full force and
effect and be binding upon the parties hereto.

     10.  Definitions. All capitalized terms used herein, but not defined
herein, shall have the same meanings given to such terms in the Lease unless
otherwise indicated.

     IN WITNESS WHEREOF, Landlord and Tenant have duly executed this First
Amendment to Lease as of the day and year first above written.

                              LANDLORD:
                              DENVER-STELLAR ASSOCIATES LIMITED
                              PARTNERSHIP, a Delaware limited partnership
                              By:  Amerimar Realty Management
                                   Co.-Colorado
                                By:  Amerimar Realty Management-
                                     Pennsylvania, its general partner
                                  By: ARC-Management Company,
                                      its general partner

                              By: /s/ David G. Marshall
                                 --------------------------------------
                                  David G. Marshall, President

Date: September 11, 1998
     -----------------------

                                       4
<PAGE>

                         TENANT:
                         PRIME RESPONSE, INC., a Delaware
                         corporation

                         By: /s/ Cathy Lewis
                            ---------------------------------
                                 Cathy Lewis
                                 Vice President of Finance

Date: 8/6/98
     ----------

                                       5
<PAGE>

                    [FIFTH FLOOR FINISH PLAN APPEARS HERE]
<PAGE>

                                   EXHIBIT C
                                   ---------

                             LEASE TERM AGREEMENT

     THIS AGREEMENT, made as of the 20th day of January, 1998, between DENVER-
STELLAR ASSOCIATES LIMITED PARTNERSHIP, a Delaware limited partnership
(hereinafter referred to as "Landlord") and PRIME RESPONSE, INC., a Delaware
corporation (hereinafter referred to as "Tenant").

                                  WITNESSETH

     WHEREAS, by Lease (hereinafter called "Lease") made as of the 20th day of
January, 1998, Landlord leased unto Tenant certain premises known as Suite
Number 500, located at 1099 Eighteenth Street, Denver, Colorado, for a term of
five (5) years, three (3) months and zero (0) days commencing on June 1, 1998,
unless sooner terminated or extended as provided therein, and

     WHEREAS, Landlord and Tenant now desire to set forth the correct
Commencement Date of the term and to adjust the Expiration Date of the Term to
provide for a full term of the Lease of FIVE years, SIX months and ZERO days.

     NOW, THEREFORE, Landlord and Tenant do hereby agree as follows:

     1.   The Term of the Lease commenced JULY 1, 1998, and shall continue
          until DECEMBER 31, 2003 unless sooner terminated or extended as
          provided therein.

     2.   Except as hereby amended, the Lease shall continue in full force and
          effect.

     3.   This Agreement shall be binding on the parties hereto, their heirs,
          executors, successors and assigns.

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed as of the day and year first above written.

                         LANDLORD:

                         DENVER-STELLAR ASSOCIATES
                         LIMITED PARTNERSHIP, a Delaware
                         limited partnership

                         By:  Amerimar Realty Management Co.-
                              Colorado

                              By:   Amerimar Realty Management-
                                    Pennsylvania, its general partner

                                    By:  ARC-Management
                                         Company, its general
                                         partner

                         By:  /s/ David G. Marshall
                            ----------------------------------------
                                  David G. Marshall, President

                         TENANT:

                         PRIME RESPONSE, INC., a Delaware
                         corporation

                         By:  /s/ Robert Fetter CEO
                            ----------------------------------------
                                         Authorized Signature (Title)
<PAGE>

                               LICENSE AGREEMENT

               (Use of Licensor's Security System and Equipment)

     THIS LICENSE AGREEMENT ("Agreement") is executed as of the 1/st/ of
October, 1998, by and between DENVER-STELLAR ASSOCIATES LIMITED PARTNERSHIP, a
Delaware limited partnership ("Licensor"), and PRIME RESPONSE, INC., a Delaware
corporation ("Licensee").

                                   RECITALS:

     A.   Licensor is the owner of a certain commercial office building located
at 1099 - 18th Street in Denver, Colorado, which is commonly known as Denver
Place Plaza Tower (the "Building").

     B.   Licensee has requested that Licensor grant to Licensee a license to
locate and install within the Building certain cables, wiring, transmission
lines, conduits, markers, signs and related facilities (collectively, the
"Equipment"). The Equipment will be used to provide certain electronic access
and security services to Licensee, its employees, licensees, and invitees at
those certain premises in the Building known as Suite 500 (the "Premises") and
leased by Licensee pursuant to that certain Office Lease between Licensor, as
landlord and Licensee, as tenant dated January 20, 1998 (the "Lease"). Licensor
has agreed to grant said license in accordance with and subject to the terms of
this Agreement.

                    GRANT OF LICENSE AND RELATED AGREEMENTS

     NOW, THEREFORE, in consideration of the foregoing Recitals and the mutual
covenants set forth herein, Licensor and Licensee, intending to be legally
bound, covenant and agree as follows:

     1.   Grant of License. Licensor hereby grants to Licensee, in accordance
with and subject to all the other provisions of this Agreement, a non-exclusive
license on, under, across and through the License Area of the Building (defined
in paragraph 2(a) below), as it may be modified from time to time as provided
below, to construct, install, inspect, maintain, repair, reconstruct and replace
the Equipment subject to the terms of this Agreement (hereinafter the
"License"), at Licensee's sole cost and expense. All such activity associated
with the construction, installation, inspection, maintenance, repair and
replacement of the Equipment is sometimes referred to hereinafter collectively
as the "Work." The License shall inure to the benefit of Licensee and its
permitted successors and assigns (as set forth in paragraph 10 hereof), and
shall be binding upon Licensor and its successors-in-interest in and to the
Building. Nothing contained in this Agreement

                                       1
<PAGE>

shall be construed as granting to Licensee any property, leasehold or ownership
rights in the Building or to create a partnership or joint venture between
Licensor and Licensee.

     2.   Conduct and Commencement of Work.

          (a)  Licensee, at its sole cost and expense, shall cause the
     preparation of and submit to Licensor plans and specifications for the
     Equipment, location of all components thereof, and all aspects of the Work
     (the "Plans"). The Plans (including any proposed modifications thereto
     after Licensor's initial approval, if any) shall be subject to Licensor's
     approval before any Work may be commenced, which approval may be withheld
     at Licensor's sole discretion. The space(s) identified in the Plans which
     are approved by Licensor as the location of the Equipment is referred to as
     the "License Area." Licensee and Licensor acknowledge that it is intended
     that the License Area shall consist of approximately 11,565 square feet of
     area located on the fifth floor of the Building (the "Primary Area"), plus
     that area identified on the Plans necessary for the routing of cable from
     the Primary Area to the Premises. It is understood and agreed that some or
     all of the License Area may be the same area of the Building which houses
     the wiring, cables, and related electronic facilities for Licensor's
     security and access system for the Building and its tenants (such wiring,
     cable and related materials being hereinafter sometimes referred to as the
     "Licensor's Equipment" and such electronic security and access system being
     hereinafter sometimes referred to as the "Licensor's Security System") and
     that, subject to the terms of this Agreement, and as outlined on the Plans,
     Licensee may utilize the Licensor's Equipment in connection with its
     installation of the Equipment and use of its access and security system,
     provided such use does not interfere in any way with the use of the
     Licensor's Equipment or Licensor's Security System or the use of the same
     by the Licensor or any other tenants in the Building.

          (b)  Licensee acknowledges and agrees that Licensor's review of the
     Plans shall be solely for Licensor's own benefit and account; by conducting
     such review and/or approving the Plans, Licensor shall not be regarded as
     undertaking any obligation for the technical or legal sufficiency, adequacy
     or safety of the Equipment or the Work, and Licensee waives and disclaims
     any such responsibility of Licensor and hereby assumes all obligations and
     duties related to such technical and legal sufficiency, adequacy and
     safety. Licensor's approval of the Plans shall not be construed to limit or
     abridge Licensee's obligations under this Agreement to any extent.

          (c)  Licensee, at its sole cost and expense, shall obtain and provide
     copies to Licensor of all requisite building permits and other governmental
     approvals prior to any and all consents that may be required therefor from
     private parties undertaking any part or all of the Work. Without limitation
     on the generality of the foregoing, Licensee acknowledges that Licensee
     shall be solely responsible for securing all

                                       2
<PAGE>

     licenses and approvals, whether governmental, quasi-governmental or private
     in nature, which are requisite to providing connections and related
     facilities for the Equipment at any locations away from the Building
     (including, without limitation, any public rights-of-way) or otherwise
     required in connection with the Work. Furthermore, Licensee shall bear all
     risks associated with any revocability of those licenses and approvals, and
     Licensor shall have no obligation or duty to Licensee in connection
     therewith. For purposes of interpreting Licensee's obligations hereunder,
     the "Work" shall include the construction, installation, inspection,
     maintenance, repair and replacement of any off-site connections and related
     facilities required for Licensee's provision of access and security
     services to the Building and/or its tenants.

          (d)  Licensee shall cause all Work to be undertaken and completed and
     the Equipment maintained in a good, safe and workmanlike manner consistent
     with the highest construction standards, in conformity with the approved
     Plans, and in compliance with all applicable laws, rules and regulations
     and any private restrictions applicable to the Work and the Owner's Rules
     and Regulations attached hereto as Exhibit A and any future modifications
                                        ---------
     thereof. Licensee shall not conduct the Work nor otherwise utilize the
     License Area in any way so as to increase Licensor's insurance payments,
     and at Licensor's option shall pay such increases. Licensee will perform
     the Work in such a manner as to not unreasonably interrupt the Building's
     normal operations (including the use of the Licensor's Security System) and
     will repair any damage that the Work causes to the Building, the Licensor's
     Equipment, the Licensor's Security System, or any other property located
     therein such that the same is in as good or better condition than existed
     immediately prior to the time of any damage. Furthermore, Licensee shall
     schedule the Work at such times and take such other measures and
     precautions as Licensor may require in order to avoid or minimize any
     interference with Building operations that may be caused by the Work;
     however, in the event of an emergency, Licensee shall have 24 hour a day, 7
     day a week access to the License Area. In connection with the Work,
     Licensee shall not enter the premises of any tenant or occupant of the
     Building without that tenant's or occupant's prior written consent. If any
     of the Work is not performed in accordance with the foregoing or any other
     requirements of this Agreement, Licensor shall have the right, but not the
     obligation, and without limiting Licensor's other remedies for such
     failure, to correct any non-complying Work after sending ten (10) days'
     notice and right to cure such nonconforming work, after which Licensee
     shall reimburse Licensor for all costs and liabilities incurred in
     connection therewith by Licensor, including attorneys' fees. No notice or
     opportunity to cure need be given by Licensor if, in Licensor's reasonable
     judgement, a hazardous condition exists or is about to exist.

          (e)  Licensee shall not disrupt, adversely affect or interfere with
     other providers of services in the Building or with any occupant's use and
     enjoyment of its leased or licensed premises or the common areas of the
     Building. Licensee agrees

                                       3
<PAGE>

     to use all efforts to ensure that the Equipment, and the installation,
     maintenance and operation thereof will in no way interfere with the use of
     the Building, including but not limited to the Licensor's use of the
     Licensor's Equipment and the Licensor's Security System, or the operation
     of any other electronic devices by Licensor or by other lessees or
     licensees of the Licensor (including but not limited to any communications
     devices). If interference shown to be caused by Licensee's Equipment, or
     the installation, operation, and maintenance thereof, shall occur, Licensor
     shall give Licensee notice thereof, and Licensee shall take immediate
     action to correct the same within twelve (12) hours of receipt of such
     notice. Licensor reserves the right to disconnect power to the Equipment if
     Licensee fails to correct such interference after proper notification and
     the expiration of the twelve (12) hour cure period. Licensor agrees to
     restore power to Licensee's Equipment after such disconnection if Licensee
     corrects the cause of the interference thereafter.

          (f)  Licensee shall not store highly flammable materials or goods,
     explosives, perishable foodstuffs, contraband, live animals, materials or
     goods which emit odors in or upon the License Area. The Licensee covenants
     that it shall not store, use or possess nor permit the storage, use or
     possession of any Hazardous Substance (hereinafter defined) upon the
     License Area. Hazardous Substance for purposes of this Agreement shall
     mean, without limitation, any flammable explosives, radon, radioactive
     materials, asbestos, urea-formaldehyde foam insulation, polychlorinated
     biphenyls, petroleum and petroleum based products, methane, hazardous
     materials, hazardous wastes, hazardous or toxic substances or related
     materials, as defined in the Comprehensive Environmental Response,
     Compensation and Liability Act of 1980, as amended (42 U.S.C. Sections 9601
     et seq.), the Hazardous Materials Transportation Act, as amended (49 U.S.C.
     -- ---
     Sections 1801, et seq.), Sections 6901, et seq.), the Toxic Substances
                    -- ---                   -- ----
     Control Act, as amended (15 U.S.C. Sections 2601 et seq.), or any other
                                                      -- ---
     similar law, rules, regulation or statute concerning the protection of the
     environment (collectively "Environmental Laws"). Licensee hereby covenants
     and agrees, at its sole cost and expense, to indemnify, protect and defend
     and save harmless the Licensor and any of its partners, employees and
     agents from and against any all damages, losses, liabilities, obligations,
     penalties, claims, litigation, demands, defenses, judgments, suits,
     actions, proceedings, costs, disbursements and/or expenses (including,
     without limitation, attorneys' and experts' fees, expenses and
     disbursements) of any kind or nature whatsoever which may at any time be
     imposed upon, incurred by or asserted or awarded against the Licensor, its
     partners, agents or employees relating to, resulting from or arising out of
     Licensee's failure to comply with its obligations under the foregoing
     paragraph or Licensee's violation of any Environmental Law with respect to
     its use of the License Area. Notwithstanding any other provision of this
     Agreement, the indemnification provisions set forth in this paragraph shall
     survive the expiration or earlier termination of this Agreement.

                                       4
<PAGE>

     3.   Cost of Work; Mechanic's Liens. All Work shall be at Licensee's sole
cost and expense, and Licensor shall not have any responsibility or liability
therefor. Licensee specifically acknowledges and agrees that Licensor has no and
will have no liability to compensate Licensee to any extent for any value that
the Equipment may add or provide to the Building, and Licensee hereby
irrevocably waives all rights that Licensee might otherwise have to claim any
mechanic's lien or similar encumbrance against the Building in connection with
the Work. Some aspects of the Work (including, without limitation, the
preparation of the Plans) may be undertaken by independent contractors of
Licensee. Before any independent contractor performs any services or labor in
connection with the Building or the Work, Licensee shall secure from each such
independent contractor a waiver of all lien rights. Each such original waiver
shall be promptly submitted to Licensor after execution.

     4.   License Fees. Licensee shall pay to Licensor the sum of Six-Thousand-
Three-Hundred Dollars ($6,300.00) for access to the License Area in 63 equal
monthly installments of $100.00 due on the 1/st/ day of each month commencing
October 1, 1998. If any payment or any part of any such payment to be made by
Licensee under the terms of this Agreement shall become overdue for a period in
excess of five days, Licensee shall pay to Licensor a "late charge" of $.05 for
each dollar so overdue for the purpose of defraying the expense incident to
handling such overdue or delinquent payment, plus interest on the overdue amount
at the rate of eighteen percent (18%) per annum from the date when such payment
was due until the date paid. Nothing herein shall be construed as waiving any
rights of Licensor arising out of any default of Licensee by reason of
Licensor's accepting any such late charge or interest; the right to collect a
late charge and interest is separate and apart from and in addition to any other
rights or remedies of Licensor. In the event Licensor brings any action against
Licensee and/or its successors or assigns as a result of any breach of this
Agreement, Licensor shall be entitled to collect reasonable attorneys' fees and
all costs incurred if Licensor prevails in said action. In addition to the
license fees as provided herein, Licensee shall pay Licensor a one-time non-
refundable administration fee (the "Administration Fee") for the administrative
costs incurred in connection with the review of the Plans and project logistics
in the amount of Five-Hundred Dollars ($500.00). Licensee shall pay the
Administration Fee at the time the first month's installment of license fees are
due under this Agreement.

     5.   Indemnity/and Hold Harmless. Licensee shall defend and indemnify
Licensor and hold Licensor harmless from any liabilities, mechanic's or other
similar types of liens, damages, penalties, fines, costs, theft, or other losses
of any nature (including consequential damages) including, without limitation,
any property damage suffered by Licensor (including but not limited to
Licensor's Equipment or Licensor's Security System), Licensee or any third
parties or any claims for personal injury and/or workmen's compensation by
Licensee or any third parties, including independent contractors and/or
employees of Licensee and/or Licensor, together with all related costs and
expenses, including reasonable attorneys' fees incurred by or claimed against
Licensor, that may arise in connection with (i) the Work or any part thereof
including any off-site connections and related facilities for the Equipment (as
referenced in subparagraph 2(c) above), (ii) any other aspects of the Work or
Licensee's use and enjoyment of the License and the Equipment including the
granting of the License by Licensor and electrical and HVAC costs attributable
to operation of the

                                       5
<PAGE>

Equipment, and (iii) any breach or default by Licensee of its obligations under
this Agreement provided that such loss, liability or damage is not caused by
Licensor's gross negligence or willful misconduct. To the extent Licensor pays
any sum which falls within the foregoing indemnity, Licensee shall reimburse
Licensor for such sum within thirty (30) days after Licensor makes demand
therefor. Licensee specifically agrees that Licensor's approval of the Plans
shall not be construed to limit the foregoing indemnity. Without limitation on
the generality of the foregoing, the foregoing indemnity shall apply to any
structural damage suffered by the Building in connection with the Work, whether
or not the Work conforms to the Plans. The provisions of this paragraph 5 shall
survive termination and expiration of this Agreement.

     6.   Completion of Work. Upon completion of the Work, Licensee shall
provide Licensor with all certificates or other approvals that are legally
required to evidence that the Work has been completed in conformity with all
applicable laws. In addition, Licensee shall furnish Licensor with a certificate
that the Work has been completed in conformity with the approved Plans, which
certification must be rendered by a licensed engineer or similar party
satisfactory to Licensor and must be in form and substance satisfactory to
Licensor. Licensee shall also supply Licensor with a complete set of "as built"
construction documents related to the Work.

     7.   Licensee's Covenants. Licensee hereby covenants and agrees:

          (a)  to keep the License Area and Equipment in good order, repair and
     condition throughout the Term of this Agreement and any renewals thereof
     and promptly and adequately repair all damage to the Building, Licensor's
     Equipment or Licensor's Security System caused by Licensee or the
     Equipment;

          (b)  to comply and remain in compliance with all federal, state and
     municipal laws, orders, rules and regulations applicable to Licensee, the
     Work and Equipment, as well as the Owner's Rules and Regulations attached
     hereto as Exhibit A and any future modifications thereof;
               ---------

          (c)  not to disrupt, adversely affect or interfere with other
     providers of services in the Building or with any occupant's or tenant's
     use and enjoyment of their leased premises or the common areas of the
     Building.

     8.   Term; Removal. The License shall remain in full force and effect for a
term of Five (5) years and Three (3) months from the date the monthly license
fee is first payable (the "Term"), unless terminated pursuant to the mutual
written agreement of the parties hereto; provided, however, that Licensor may
terminate the License upon ten (10) days' written notice (and opportunity to
cure) in the event that Licensee does or permits any one of the following:

          (a)  fails to pay any installment or other amount when due pursuant to
     this Agreement;

                                       6
<PAGE>

          (b)  commits any material breach or default of its obligations
     hereunder or under any other agreement, lease or license with Licensor
     and/or any of its affiliates;

          (c)  abandons or deserts the Building or Equipment during the Term or
     any renewal thereof or Licensee removes (and does not replace or substitute
     equipment for) all or a substantial portion of the Equipment, including
     equipment in the License Area, from the Building;

          (d)  fails to completely construct and install its Equipment in the
     Building within 90 (ninety) days of the date of this Agreement; or

          (e)  voluntarily or involuntarily files bankruptcy or makes a general
     assignment for the benefit of creditors.

     No notice or opportunity to cure need be given by Licensor if, in its
reasonable judgment, a hazardous condition exists or is about to exist.
Licensor's right of termination shall be cumulative with and in addition to all
other rights and remedies afforded to Licensor at law or in equity for such
breach or default. Upon any termination of the License, Licensee shall remove
the Equipment and restore the License Area to its original condition. Licensee
shall be obligated to complete any such removal and restoration within sixty
(60) days after the termination or expiration of the License. If any Equipment
is not so removed in a timely manner, then the remaining Equipment shall, at
Licensor's election, become part of the improvements constituting the Building,
and all incidents of ownership of the Equipment shall immediately vest in
Licensor or, at Licensor's option, Licensor may remove the Equipment and restore
those portions of the Building impacted by the Work and the costs for such
removal shall be charged to Licensee as additional license fees. In connection
with any removal, Licensee shall simultaneously restore those portions of the
Building impacted by the Work to substantially the same condition existing
immediately prior to the commencement of the Work. For purposes of applying the
indemnity provisions of paragraph 5 above, all activity related to such removal
and restoration shall be regarded as part of the Work.

     If Licensee exercises its option to renew the Lease pursuant to Paragraph
31 of the January 20, 1998 Addendum thereto (the "Addendum"), the Term of this
Agreement shall also be renewed for the Renewal Term, as defined in the
Addendum, without notice from Licensee to Licensor other than the notice
required to be given pursuant to Paragraph 31(a) of the Addendum. In the event
of such renewal, Licensor shall pay Licensee a monthly License Fee of $100.00
payable on the 1st day or each month during the Renewal Term. All other
provisions and conditions of this Agreement shall remain in full force and
effect throughout the Renewal Term.

     9.   Effect of Prior License or Easement Agreement(s); Priority.

          (a)  Licensee acknowledges that the Building is or may already be
     subject to other licenses and license and/or easement agreements.
     Licensee's rights

                                       7
<PAGE>

     hereunder to use and enjoy the License is subject to and qualified in all
     respects by the obligations of Licensor under all Prior licenses, license
     and easement agreements (including, without limitation, the obligation of
     Licensor to grant additional licenses, license and easement rights
     affecting the Building). Licensee agrees that, to the extent the Equipment
     must be relocated or otherwise modified to accommodate preexisting rights
     in favor of prior grantees of licenses/easements or future
     licenses/easements as deemed reasonably necessary by Licensor, Licensee
     shall undertake such relocation or modification at its sole cost and
     expense and all such activity shall be considered a part of the Work. In
     the event Licensee reasonably determines that the alternative location for
     the License Area (or the Equipment pursuant to Paragraph 9(c) below) chosen
     by Licensor is infeasible, Licensee may terminate this Agreement upon
     giving Licensor thirty (30) days' written notice and opportunity to provide
     alternatives.

          (b)  Licensee further acknowledges and agrees that, notwithstanding
     any provisions of this Agreement that may indicate to the contrary, all
     rights and interests of Licensee under this Agreement are and shall be
     subject and subordinate to all pre-existing interests in the Building
     having priority over the License including, without limitation, the
     interest of all persons or entities which have a lien on the Building.
     Licensee acknowledges and agrees that Licensor shall have no liability to
     Licensee in connection with any exercise or enforcement of those pre-
     existing interests which may affect Licensee's interests hereunder.
     Licensee further acknowledges and agrees that it has no rights to any
     common areas in the Building under this Agreement, none of such common
     areas of the Building shall be considered any part of the License Area
     under this Agreement, and no Equipment shall be installed in any of the
     common areas of the Building, including but not limited to any
     communications closets located in any of the common areas of the Building.

          (c)  In the event Licensor requests that the Equipment be relocated or
     that the License Area otherwise be modified, such that the License Area
     shall be moved to a different portion of the Building from its then current
     location, Licensee shall undertake such relocation or modification at its
     sole cost and expense, and the area to which the License Area is relocated
     shall henceforth be referred to as the License Area.

     10.  Successors and Assigns.

          (a)  Licensor shall be permitted to assign its rights hereunder to any
     of its successors in interest to the Building and to any mortgagee of
     Licensor's interests in the Building. Licensee shall not be permitted to
     assign or delegate any of its rights or obligations hereunder without the
     prior express written consent of Licensor, which may be withheld in
     Licensor's sole discretion; any assignment attempted by Licensee

                                       8
<PAGE>

     in violation of the foregoing shall be void and of no force or effect at
     Licensor's option.

     11.  Insurance. Licensee shall obtain and maintain such insurance,
including through a blanket policy, as will fully protect both Licensee and
Licensor from claims by employees of Licensee under all applicable workers'
compensation and/or employers' liability laws, including any employers'
disability insurance laws, and from all claims for damage to property or for
personal injury, including death to anyone whomsoever, that may arise from the
Work, the Equipment or any operations in connection with the performance of the
services in the Premises by Licensee, or by anyone directly or indirectly
engaged or employed by Licensee. Licensee shall provide Licensor with
certificates evidencing the required coverage prior to Licensor commencing any
Work in the Building.

     Notwithstanding the generality of the foregoing, Licensee's general
liability insurance shall be a minimum of $2 million per occurrence, which may
take the form of $1 million in primary coverage with $1 million in excess
coverage, which must include a provision preventing cancellation of such policy
except following 30 days' prior written notice to Licensor. Licensor shall be
listed as an "additional insured" on said general liability policy. Licensee's
insurance carrier shall have a Best Rating of at least B + or better.

     12.  Non-Recourse Liability. Licensor and each of its successors-in-
interest to the Building shall have liability (as further outlined below) only
for those obligations of Licensor under this Agreement, if any, which accrue
during the term of that party's ownership of the Building, and each such party
shall have no liability for any such obligation that accrues either before or
after the time of that party's ownership of the Building. Furthermore, in any
event, any mortgagee of Licensor or its successors-in-interest that acquires
Licensor's interest in the Building by foreclosure or any conveyance in lieu
thereof or otherwise shall not have any liability whatsoever for any obligations
of Licensor hereunder. Any liability for damages or breach or nonperformance by
Licensor, or arising out of the subject matter of this Agreement or the
relationship created hereby, shall be collectible only out of Licensor's
interest in the Building and no personal liability is assumed by, or shall at
any time be asserted against, Licensor, its partners, affiliates, agents,
attorneys, servants and employees, or any of its or their successors or assigns;
all such liability, if any, being hereby expressly waived and released by
Licensee.

     13.  Other Defaults. Any default by Licensee in discharging any of its
obligations under the Lease, including but not limited to the payment of Rent
thereunder, shall be a default of Licensee's obligations under this Agreement,
and Licensor may exercise any of the rights and remedies available to it as if
Licensee was in default hereunder. Any default by Licensee hereunder, including
but not limited payment of the License Fee, shall be a default of Licensee's
obligations under the Lease, and Licensor may exercise any of the rights and
remedies available to it under the Lease as if Licensee was in default
thereunder.

                                       9
<PAGE>

     14.  Governing Law. This Agreement and all the provisions hereof shall be
governed by and construed in accordance with the laws of the State of Colorado.

     15.  Notices. All notices or demands pursuant to this Agreement shall be in
writing and sent by first class mail, postage prepaid or by commercial overnight
delivery, prepaid, to the parties at their addresses provided below, or to such
other address as a party may specify by notice to the other party:

          LICENSEE:

                    Prime Response, Inc.
                    1099 18/th/ Street, Suite 500
                    Denver, CO 80202

          LICENSOR:

                    Denver-Stellar Associates Limited Partnership
                    c/o Amerimar Realty Management Co.-Colorado
                    999 - 18th Street, Suite 1000
                    Denver, Colorado 80202
                    Attention: General Manager

          with a copy to:

                    Slivka Robinson Waters & O'Dorisio, P.C.
                    1099 - 18th Street, Suite 2600
                    Denver, Colorado 80202
                    Attention: John W. O'Dorisio, Jr., Esq.

     16.  Security Deposit. The Licensee shall keep on deposit with the Licensor
at all times during the term of this Agreement, a security deposit (the
"Security Deposit") in the amount of One-Thousand-Two-Hundred Dollars
($1,200.00) as security for the payment by the Licensee of the rent, license
fees, or any other sums due under this Agreement and for the faithful
performance of all the terms, conditions and covenants of this Agreement. If at
any time during the term of this Agreement the Licensee shall be in default in
the performance of any provision of this Agreement, the Licensor may (but shall
not be required to) use any such deposit, or so much thereof as necessary, in
payment of any rent or any other sums due under this Agreement in default, in
reimbursement of any expense incurred by the Licensor and in payment of the
damages incurred by the Licensor by reason of the Licensee's default, or at the
option of the Licensor, the same may be retained by the Licensor as liquidated
damages. In such event, the Licensee shall, on written demand of the Licensor,
forthwith remit to the Licensor a sufficient amount in cash to restore such
deposit to its original amount. If such deposit has not been utilized as
aforesaid, such deposit, or as much thereof as has not been utilized for such
purposes, shall be refunded to the Licensee, without interest, upon full
performance of this

                                      10
<PAGE>

Agreement by the Licensee. Licensor shall have the right to commingle such
deposit with other funds of the Licensor. Licensor shall deliver the funds
deposited herein by the Licensee to any purchaser of the Licensor's interest in
the License Area in the event such interest be sold, and thereupon, the Licensor
shall be discharged from further liability with respect to such deposit.
Notwithstanding the above provisions of this Section, if claims of the Licensor
exceed the deposit for therein, the Licensee shall remain liable for the balance
of such claims.

     17.  Miscellaneous.

          (a)  The paragraph headings contained herein are intended for
     convenience and reference only and are not intended to define, limit, or
     describe the scope or intent of any provision of this Agreement.

          (b)  Licensor makes no warranty or representation that the License
     Area or any part or all of the Building is suitable for the use
     contemplated by this Agreement, it being assumed that Licensee has
     satisfied itself thereof. Licensee has inspected the anticipated License
     Area and the Building; accepts the same "AS IS", and agrees that Licensor
     is under no obligation to perform any Work or provide any labor or
     materials to prepare, modify and/or alter the License Area or the Building
     for Licensee.

          (c)  Except as otherwise stated herein, no waiver of any breach of
     this Agreement or any of the terms hereof shall be effective unless such
     waiver is in writing and signed by the party against whom such waiver is
     claimed. No waiver of any breach shall be deemed to be a waiver of any
     other or subsequent breach. All prior or contemporaneous understandings and
     agreements between the parties which relate to this Agreement are merged
     into this Agreement which alone fully and completely expresses their
     agreement. Neither party is relying upon any statement or representation by
     the other not embodied in this Agreement.

          (d)  Licensor and Licensee acknowledge that each has carefully
     reviewed this Agreement and that the normal rules of construction whereby
     ambiguities in a contract are to be construed against the drafter shall not
     be employed in the interpretation of this Agreement.

          (e)  In the event that a court of competent jurisdiction enters an
     order of judgment declaring any material provision of this Agreement to be
     invalid and/or unenforceable, the remainder of this Agreement shall
     continue in full force and effect, such remaining provisions being deemed
     modified to the extent necessary to comply with any court order and/or
     judgment and applicable law.

          (f)  Licensee shall not place signs on any of the doors or corridors
     leading to the License Area. Licensor shall have the right, at its option,
     at Licensee's own

                                      11
<PAGE>

     cost and expense, to remove any signs placed by Licensee without Licensor's
     prior written consent, and to repair any damage caused by such signs.

          (g)  Licensor shall not be liable to Licensee for any loss or damage
     to any property or person occasioned by theft, fire, act of God, public
     enemy, injunction, riot, strike, insurrection, war, court order,
     requisition, or order of governmental body or authority or by any other
     cause. Nor shall Licensor be liable for any damage or inconvenience which
     may arise through (a) the leasing or licensing of other space within the
     Building to whomsoever Licensor chooses for whatever use is allowed by
     Licensor; (b) repair or alteration of any part of the Building or License
     Area or the construction of improvements for tenants or other licensees in
     the Building, it being specifically acknowledged and agreed by Licensee
     that Licensor will, as a part of Licensor's leasing and licensing of other
     space within the Building, be conducting construction work in order to
     prepare space in the Building, from time to time, for other tenants and
     licensees; or (c) Licensee's use of the Licensor's Equipment or Licensor's
     Security System as provided in the Plans and in this Agreement, it being
     specifically acknowledged and agreed by Licensee that its use of the
     Licensor's Equipment and/or Licensor's Security System is at its own risk,
     and that Licensor makes no representations regarding the same.

          (h)  Licensee and Licensor agree not to record this Agreement or any
     memorandum thereof unless required by governmental action or franchise
     agreement. In the event that recordation is so required, the recording
     party agrees to promptly provide the other party with a copy of this
     Agreement so recorded and, promptly upon termination of this Agreement, to
     join with the other party in executing and recording a notice of
     termination in the appropriate real property records.

     IN WITNESS WHEREOF, Licensor and Licensee have entered into this License
Agreement effective as of the date first above written.

                                 LICENSEE:

                                 PRIME RESPONSE, INC., a Delaware
                                 corporation

                                 By: /s/ Cathy Lewis
                                    -------------------------------------
                                 Name:   Cathy Lewis
                                 Title:  Vice President, Finance

                                      12
<PAGE>

                                   LICENSOR:

                                   DENVER-STELLAR ASSOCIATES
                                   LIMITED PARTNERSHIP, a Delaware
                                   limited partnership

                                   By: Amerimar Realty Management Co.-
                                       Colorado, a Colorado
                                    By: Amerimar Realty Management-
                                        Pennsylvania, its general partner
                                     By: ARC - Management Company, its
                                         general partner

                                   By: /s/ David G. Marshall
                                      --------------------------------
                                       David G. Marshall, President

                                      13
<PAGE>

                                   EXHIBIT A
                                   ---------

                             RULES AND REGULATIONS

     Rules and Regulations, to Lease between DENVER-STELLAR ASSOCIATES LIMITED
PARTNERSHIP, a Delaware limited partnership, as Landlord ("Landlord")and PRIME
RESPONSE, INC., a Delaware corporation as tenant ("Tenant"), pertaining to
certain space in Denver Place Plaza Tower, 1099 18th Street, Denver, Colorado
80202.

          (a)  Any sign, lettering, picture, notice, or advertisement installed
     within Tenant's Premises which is visible to the public from within the
     Building shall be installed at Tenant's cost and in such manner, character
     and style as Landlord may approve in writing. No sign, lettering, picture,
     notice or advertisement shall be placed on any outside window or in any
     position so as to be visible from outside the Building.

          (b)  The use of the name of the Building or of pictures or
     illustrations of the Building in advertising or other publicity, without
     prior written consent of Landlord, is prohibited.

          (c)  Tenant, its subtenants and its and their customers, invitees,
     licensees, and guests

               (i)    shall not obstruct and shall not use for any purpose other
          than ingress and egress, the sidewalks, entrances, passages, courts,
          corridors, vestibules, halls, elevators and stairways in and about the
          Building;

               (ii)   shall not place objects against glass partitions or doors
          or windows or adjacent to any open common space which would be
          unsightly from the Building corridors or from the exterior of the
          Building, and will promptly remove the same upon notice from Landlord;

               (iii)  shall not make noises, cause disturbances, create
          vibrations, odors or noxious fumes or use or operate any electrical or
          electronic devices or other devices that emit sound waves or are
          dangerous to other tenants and occupants of the Building or that would
          interfere with the operation of any device or equipment or radio or
          television broadcasting or reception from or within the Building or
          elsewhere, and shall not place or install any projections, antennae,
          aerials or similar devices inside or outside of the Premises;

               (iv)   shall not make any room-to-room canvass to solicit
          business from other tenants in the Building, and shall not exhibit,
          sell or offer to sell, use, rent or exchange any item or services in
          or from the Premises unless ordinarily embraced within the Tenant's
          use of the Premises as specified in its lease;

               (v)    shall refrain from attempting to adjust any controls;

               (vi)   shall not waste, and shall not suffer or permit to be
          wasted, electricity or water and shall cooperate fully with Landlord
          to assure the most effective operation of the Building's heating and
          air conditioning;

               (vii)  shall keep public corridor doors closed;

               (viii) shall neither install nor operate machinery or any
          mechanical devices of a nature not directly related to Tenant's
          ordinary use of the Premises without the written permission of the
          Landlord;

               (ix)   shall not use rest rooms or water fixtures for any purpose
          other than that for which they are designed;
<PAGE>

               (x)    shall not mark upon, paint, cut, drill into, drive nails
          or screws into, or in any way deface the walls, ceiling partitions or
          floors of the leased Premises or of the Building;

               (xi)   shall not unduly obstruct any pipes, conduits and ducts in
          the Premises; and

               (xii)  shall use chair pads, to be furnished by Tenant, under all
          rolling and ordinary desk chairs in the carpeted areas.

          (d)  Tenant assumes full responsibility for protecting its space from
     theft, robbery and pilferage, which includes keeping doors locked and other
     means of entry to the Premises closed and secured.

          (e)  Peddlers, solicitors and beggars shall be reported to the office
     of the Building or as Landlord otherwise requests.

          (f)  No person or contractor not employed by Landlord shall be used to
     perform window washing, cleaning, or other work in the Premises.

          (g)  Unless Landlord so consents, Tenant shall not, and Tenant shall
     not permit or suffer anyone to:

               (i)    Cook in the premises;

               (ii)   Place vending or dispensing machines of any kind in the
          Premises; or

               (iii)  At any time sell, purchase or give away, or permit the
          sale, purchase or gift of, food in any form.

               (iv)   Use the Premises for lodging or for any immoral or illegal
          purposes.

               (v)    Use the Premises to engage in the manufacture or sale of,
          or permit tile use of, any spirituous, fermented, intoxicating or
          alcoholic beverages on the Premises.

               (vi)   Use the Premises to engage in the manufacture or sale of,
          or permit the use of, any illegal drugs.

          (h)  No furniture shall be placed in front of the building or in any
     lobby or corridor, without the prior written consent of Landlord.  Landlord
     shall have the right to remove all non-permitted signs and furniture,
     without notice to Tenant, at Tenant's expense.

          (i)  No animals are allowed in the Building.

          (j)  No lock or other security device shall be placed by Tenant on any
     door in the Building without the Building manager being kept furnished with
     two of the keys, cards or other means of access therefore.  At the
     termination of its tenancy, Tenant shall promptly deliver to Landlord all
     keys, entry cards and other means of access to offices, rest rooms and
     vaults.

          (k)  The use of oil, gas or inflammable liquids for heating, lighting
     or any other purpose is expressly prohibited.  Explosives or other
     hazardous articles shall not be brought into the Building.

          (l)  Electric floor space heaters, humidifiers or A/C fans are not
     permitted.

          (m)  Landlord shall have the right to approve or disapprove the movers
     or moving company employed by Tenant.  Tenant shall cause said movers to
     use only the loading facilities and elevator designated by Landlord.  In
     the event Tenant's movers damage the elevator or any part of the Building,
     Tenant shall forthwith pay to Landlord the amount required to repair said
     damage.
<PAGE>

          (n)  If any Tenant desires telegraphic, telephonic, computer or other
     electric connections, Landlord, or its agents, will direct the electricians
     as to where and how the wires may be introduced, and without such
     directions, no boring or cutting for wires will be permitted.  Any such
     installation and connection shall be made at Tenant's expenses, and, at
     Landlord's option, shall be removed at Tenant's expense at the expiration
     or termination of its Lease.

          (o)  Except for the following smoking areas specifically designated by
     Landlord, the outdoor Plaza level of 1099 - 18th Street, the outdoor areas
     at the corner of 18th and Champa and 19th and Curtis and the Smoke Haus in
     the mall, all common areas of the building, including all sidewalks,
     entries, passages, stairways, elevators, restrooms, lobbies and hallways,
     shall be non-smoking areas.  Tenant shall be responsible to prevent its
     employees, agents, visitors, customers and guests from smoking in such
     common areas.

          (p)  During the normal office hours of 6:00 a.m. to 6:00 p.m., Monday
     through Friday, Tenant and its employees and agents shall observe the
     building dress code, which requires a neat and clean appearance and
     prohibits the wearing of cutoffs and ragged, torn, ripped, rent or holey
     apparel.

          (q)  The Landlord reserves the right to modify and make such other and
     further reasonable rules and regulations as in its judgment may, from time
     to time, be needful and desirable for the safety, security, care and
     cleanliness of the Premises and preservation of good order and therein.

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