<PAGE>   1

                                                                   EXHIBIT 10.16

Property:  CROWN PLAZA BUSINESS PARK


                                 LEASE AGREEMENT
                                    (OFFICE)


                                TABLE OF CONTENTS


<TABLE>
<S>      <C>                                                                                                          <C>
1.       Definitions and Basic Provisions ........................................................................... 1

2.       Lease of Premises; Parking Privileges ...................................................................... 2

3.       Services by Landlord ....................................................................................... 2

4.       Adjustment of Base Rental .................................................................................. 3

5.       Electricity ................................................................................................ 4

6.       Payments and Performance ................................................................................... 5

7.       Installation of Improvements; ADA Compliance ............................................................... 5

8.       Completion of Improvements and Commencement of Rent ........................................................ 5

9.       Limited Right to Calculate Rentable Space; Subsequent Liquidation .......................................... 5

10.      Repairs and Reentry ........................................................................................ 6

11.      Alterations and Additions by Tenant ........................................................................ 6

12.      Entry by Landlord .......................................................................................... 7

13.      Mechanic's Liens ........................................................................................... 7

14.      Tenant's Use ............................................................................................... 7

15.      Laws and Regulations; Rules of the Building  ............................................................... 7

16.      Indemnity, Liability and Loss or Damage .................................................................... 8

17.      No Subrogation; Insurance .................................................................................. 8

18.      Fire and Casualty .......................................................................................... 9

19.      Condemnation ............................................................................................... 9

20.      Intentionally Deleted....................................................................................... 9

21.      Assignment and Subletting .................................................................................. 10

22.      Holding Over ............................................................................................... 11

23.      Abandoned Property ......................................................................................... 11
</TABLE>



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<TABLE>
<S>      <C>                                                                                                          <C>
24.      Taxes ...................................................................................................... 12

25.      Transfer of Landlord's Rights .............................................................................. 12

26.      Default .................................................................................................... 12

27.      Security Deposit ........................................................................................... 15

28.      Intentionally Deleted....................................................................................... 15

29.      Remedies ................................................................................................... 15

30.      Joint and Several Liability ................................................................................ 16

31.      Constructive Eviction ...................................................................................... 16

32.      Building Name .............................................................................................. 16

33.      Subordination .............................................................................................. 16

34.      Lease Certificates; Financial Statements ................................................................... 17

35.      Limitation of Landlord Liability ........................................................................... 17

36.      Consents ................................................................................................... 17

37.      Notices .................................................................................................... 17

38.      Brokerage .................................................................................................. 18

39.      Force Majeure .............................................................................................. 18

40.      No Third Party Beneficiary ................................................................................. 18

41.      Severability ............................................................................................... 18

42.      Binding Effect ............................................................................................. 18

43.      Applicable Law; Consent to Jurisdiction .................................................................... 18

44.      Entire Agreement; No Warranties ............................................................................ 18

45.      NO IMPLIED REPRESENTATIONS ................................................................................. 19

46.      Effective Date ............................................................................................. 19
</TABLE>



Exhibits

Exhibit A:        Legal Description of the Land
Exhibit B:        Floor Plan(s) of the Premises
Exhibit C:        Parking Privileges
Exhibit D:        Leasehold Improvements Agreement
Exhibit E:        Building Rules and Regulations
Rider 101:        Tenant's Option to Renew
Rider 102:        Tenant's Right of First Refusal to Lease Additional Space
Rider 103:        Project Description and Application
Rider 104:        Special Sign Rights for Tenant



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                                 LEASE AGREEMENT
                                    (OFFICE)



         THIS LEASE AGREEMENT (this "LEASE") is entered into by the Landlord and
Tenant hereinafter named.

         1. DEFINITIONS AND BASIC PROVISIONS. The terms defined below shall have
the respective meanings stated when used elsewhere in this Lease, and such terms
and the following basic provisions constitute an integral part of this Lease:

         (a) "LANDLORD": CHARTER CROWN PLAZA PARTNERS, L.P., a Texas limited
                         partnership.

         (b) "TENANT": MigraTEC, Inc.

         (c) "PREMISES": certain space in Landlord's building (the "BUILDING")
located at 11494 Luna Road, in the City of Farmers Branch, Texas, on a tract of
land (the "LAND") situated in the City of Farmers Branch, Texas, being described
on Exhibit A attached hereto and made a part hereof for all purposes. The
Premises are located on the first (1st) floor(s) of the Building, Suite(s) 100,
as shown on the floor plan(s) attached hereto as Exhibit B and made a part
hereof for all purposes. Subject to Paragraph 9 below, the parties hereby agree
that for purposes of this Lease the Premises is deemed to contain approximately
9,988 square feet of Rentable Space (as defined below), and that there are
approximately 27,790 square feet of Rentable Space in the Building.

         (d) "LEASE TERM": a period of 39 months, commencing on May 1, 2000 (the
"COMMENCEMENT DATE"), subject to the possibility of extension as explained in
Paragraph 8 below.

         (e) "BASE RENTAL": Months 1-3 - $0.00 per month and Months 4-39 -
$14,982.00 per month, plus $500.00 per month for every month Tenant has a sign
on the Building and does not occupy the entire 1st floor which Tenant agrees to
pay to Landlord at the following address: 5757 Alpha Road, Suite 101, Dallas,
Texas 75240 (or at such other place as Landlord may designate from time to time
in writing) in monthly installments, in advance and without demand on the first
day of each calendar month during and throughout the Lease Term.

         (f) "PREPAID RENTAL": $14,982.00, representing payment of Base Rental
for the fourth month of the Lease Term, to be paid on the date of execution of
this Lease.

         (g) "SECURITY DEPOSIT": $7,491.00, to be paid on the date of the
execution of this Lease, and held by Landlord pursuant to the provisions of
Paragraph 27 of this Lease.

         (h) "SOLE PERMITTED USE": General office use, consistent with a
reputable office building and subject to Paragraph 14 and other relevant
provisions of this Lease.

         (i) "BASE EXPENSE AMOUNT": The aggregate of Operating Expenses incurred
in connection with the Building during calendar year 2000.

         (j) "LEASING AGENT(S)": Fobare Commercial, Inc. (representing Landlord)
and Dillon Corporate Services, Inc. (representing Tenant).

         (k) "PROPERTY MANAGER": Fobare Commercial, Inc., 5757 Alpha Road, Suite
101, Dallas, Texas 75240, subject to change by Landlord upon written notice to
Tenant.

         (l) "SUBMISSION DATES": N/A and N/A, as those dates are referred to the
Paragraph 4 of the Leasehold Improvements Agreement attached as Exhibit D of
this Lease.



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<PAGE>   4

         (m) "RENTABLE SPACE": The total area attributable to a leased premises
within the Building, i.e., being deemed by the parties to be appropriate for
purposes of determining the Base Rental, the Allowance, rental adjustments, etc.
under this Lease, with such total attributed area being determined by (a) using
the American National Standard method for measuring Rentable Area in office
buildings, as described in the pamphlet entitled "Standard Method for Measuring
Floor Area in Office Buildings", published by the Building Owners and Managers
Association International (ANSI/BOMA Z65.1-1996), and then (b) adjusting the
floor-by-floor results thus achieved by the factor being used by Landlord to
more uniformly allocate to the tenants in the Building the first floor lobby,
the elevator lobbies and the other common areas of the Building.

         (n) "NORMAL BUSINESS HOURS": 7:00 a.m. until 6:00 p.m. on weekdays
(except holidays, as defined below), and from 8:00 a.m. until 1:00 p.m. on
Saturdays (except holidays). For purposes of this Lease, holidays are deemed to
mean the following:

                  January 1st                        New Years Day
                  Last Monday in May                 Memorial Day
                  July 4th                           Independence Day
                  First Monday in September          Labor Day
                  Fourth Thursday in November
                  plus Friday following              Thanksgiving Holidays
                  December 25th                      Christmas Day

         2. LEASE OF PREMISES; PARKING PRIVILEGES. (a) In consideration of the
obligation of Tenant to pay rent as provided in this Lease, and in further
consideration of the other terms, covenants and conditions of this Lease,
Landlord hereby leases to Tenant, and Tenant hereby takes from Landlord, the
Premises for the Lease Term specified herein, all upon and subject to the terms
and conditions set forth in this Lease. Landlord hereby covenants that Tenant,
upon paying rent as herein reserved, and performing all covenants and agreements
contained in this Lease on the part of Tenant, shall have quiet and peaceful
possession of the Premises.

         (b) In addition, at all times during the Lease Term, and conditioned
upon the Lease being in full force and effect and there being no uncured default
under this Lease by Tenant, Landlord hereby agrees to make parking privileges
available to Tenant, as explained on, and governed by, Exhibit C attached to
this Lease. In this regard, Tenant acknowledges that in order for Landlord to be
able to comply with parking allotments for all tenants in the Building, Tenant
must assure that the aggregate of all parking utilized by Tenant, its owners,
officers, employees, agents and invitees, does not exceed the parking allotment
for Tenant as specified in Exhibit C.

         3. SERVICES BY LANDLORD. At all times during the Lease Term, and
conditioned upon the Lease being in full force and effect and there being no
uncured default under this Lease by Tenant, Landlord shall furnish the following
services to the Premises, all of such services to be at Landlord's cost and
expense except as specifically provided to the contrary elsewhere in this Lease:

         (a) Cold and warm water at those points of supply provided for general
use of tenants in the Building.

         (b) Heated and refrigerated air conditioning in season during Normal
Business Hours and at such temperatures and in such amounts as are reasonably
considered by Landlord to be standard. Such services at all other times and on
Sundays and holidays shall be furnished only at Landlord's discretion and in any
event upon forty-eight (48) hours prior written request by Tenant, who shall
bear the entire cost thereof. Whenever machines or equipment that generate
abnormal heat and affect the temperature otherwise maintained by the air
conditioning system are used in the Premises, Landlord shall have the right to
install supplemental air conditioning units in the Premises; and the cost
thereof, including the cost of installation, operation, use and maintenance,
shall be paid by Tenant to Landlord promptly on demand.



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<PAGE>   5

         (c) Elevator service in common with other tenants for ingress and
egress from the Premises, provided that Landlord may reasonably limit the number
of elevators to be in operation at times other than Normal Business Hours.

         (d) Janitorial cleaning services as may, in the reasonable judgment of
Landlord, be required in the normal operation of the Building (but no less
frequently than five times per week).

         (e) Electric current in the manner and to the extent reasonably deemed
by Landlord to be standard for office use.

The failure to any extent to furnish or any stoppage of these defined utilities
and services resulting from any cause whatsoever shall not render Landlord
liable in any respect for damages to either person, property or business, nor be
construed as an eviction of Tenant, nor entitle Tenant to any abatement of rent,
nor relieve Tenant from fulfillment of any covenant or agreement contained
herein. Should any malfunction of the Building improvements or facilities occur
for any reason, Landlord shall use reasonable diligence to repair same promptly.
Tenant shall have no claim for rebate or abatement of rent or damages on account
of such malfunction or of any interruptions in service occasioned thereby or
resulting therefrom; provided, however, that if any interruption or cessation of
service continues for ten (10) consecutive business days after written notice
from Tenant to Landlord (and to any mortgagee of Landlord of whom Tenant has
received written notice, designating a specific address for notice to such
mortgagee), identifying the problem with reasonable specificity and being
labeled "URGENT/IMMEDIATE ACTION REQUIRED" in all capital letters, and if such
interruption or cessation after the 10-business-day cure period causes the
Premises to be untenantable in the reasonable judgment of Tenant, then
notwithstanding any provision of this Lease to the contrary, Tenant's Base
Rental and Tenant's share of Operating Expenses under this Lease will abate as
of the eleventh (11th) business day and continue abated until the service is
resumed.

         4. ADJUSTMENT OF BASE RENTAL. The Base Rental payable pursuant to this
Lease shall be adjusted upward from time to time in accordance with the
following provisions:

         (a) Tenant's Base Rental is based, in part, upon the assumption that
Landlord is contributing as its share of the annual Operating Expenses [as
defined in Paragraph 4(e) hereof] of the Building the Base Expense Amount.
Tenant shall during the term of this Lease pay, as an adjustment to Base Rental
pursuant to this Lease, an amount equal to the product of the following: (i) the
excess (the "EXCESS"), if any, from time to time of the Operating Expenses in
the Building over the Base Expense Amount, times (ii) a fraction, the numerator
of which is the net rentable space in the Premises and the denominator of which
is the net rentable space in the Building. Prior to the commencement of each
calendar year of Tenant's occupancy, Landlord shall make a good faith estimate
of the Excess, if any, for such upcoming calendar year and upon thirty (30)
days' written notice to Tenant shall require the monthly payment of Base Rental
to be adjusted in accordance with such estimate. Tenant's proportionate share of
any such estimated Excess shall be payable in equal monthly installments over
the remaining months of the calendar year after notice of such estimate is
delivered to Tenant. Any amounts paid based on such an estimate shall be subject
to adjustment pursuant to Paragraph 4(b) when actual Operating Expenses are
available for each calendar year.

         (b) By April 1 of each calendar year during Tenant's occupancy, or as
soon thereafter as practical, Landlord shall furnish to Tenant a statement of
Landlord's actual Operating Expenses for the previous calendar year. If any
additional Base Rental collected for a prior year, as a result of Landlord's
estimate of the Excess, is in excess of the additional Base Rental actually due
during such prior year, then Landlord shall refund to Tenant any overpayment (or
at Landlord's option, apply such amount against rentals due or to become due
hereunder). Likewise, Tenant shall pay to Landlord, on demand, any underpayment
with respect to the prior year.

         (c) Tenant shall have the right at any time within 180 days after the
conclusion of a calendar year (but not after such 180-day period and not more
frequently than once per calendar year), following prior written notice to
Landlord, to audit, at Tenant's expense, Landlord's books and records relating
to Operating Expenses for such calendar year, or at Landlord's sole discretion,
Landlord will provide such audit prepared by an independent certified public
accountant.



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         (d) Notwithstanding anything to the contrary contained herein, if the
Building is not fully occupied during any calendar year of the Lease Term,
Operating Expenses and the Excess for purposes of Paragraphs 4(a) and 4(b)
hereof shall be determined as if the Building had been fully occupied during
such year and Operating Expenses had been in an amount which would be normal if
the Building were fully occupied. For the purposes of this Lease, "fully
occupied" shall mean (i) occupancy of 95% of the Rentable Space in the Building
if the occupancy of the Building is less than 95% of said Rentable Space, or
(ii) the actual percentage of occupancy of the net rentable space in the
Building if the occupancy of the Building is equal to or greater than 95% of
said net rentable space.

         (e) The term "Operating Expenses" shall mean all costs of management,
operation, and maintenance of the Land, the Building, and all other improvements
on the Land and all appurtenances thereto, including the costs of maintaining
any common facilities allocated from time to time to the Building, all accrued
and based on an annual period consisting of a calendar year, as determined by
generally accepted accounting principles. By way of illustration but not
limitation, Operating Expenses shall include expenditures for maintenance and
repairs; a reasonable amortization of any capital expenditures incurred by
Landlord with a principal purpose to (i) effect a reduction in the Operating
Expenses of the Building, or (ii) keep the Building in compliance with all
applicable governmental rules and regulations from time to time; assessments and
governmental charges (including taxes on rents or services); ad valorem property
taxes with respect to such year; charges for electricity, water, sewerage, and
gas; cleaning, including supplies, janitorial services and pest control;
licenses, permits and inspection fees; refuse collection; insurance;
administrative expenses, including salaries and other expenses for labor and
management, office equipment, telephone, and supplies; management fees payable
by Landlord with respect to the Land, Building and common facilities; a
reasonable allocation of the salary and other compensation paid to Landlord's
director of engineering and/or operations; fire protection; snow and ice
removal; landscape maintenance; professional services; and security (if and to
the extent provided by Landlord, i.e., with Landlord making no representation or
warranty to Tenant in this regard). The following shall be excluded from
Operating Expenses: depreciation of the original construction of the Building;
capital expenditures other than those referenced in the previous sentence; cost
of Building alterations or renovations for other tenants in the Building;
advertising; commissions paid for leasing; cost of repairs occasioned by fire,
windstorm, or other casualty (but only to the extent reimbursed by insurance
proceeds); and wages, salaries, or other compensation paid to any executive
above the grade of building manager (i.e., with the director of engineering
and/or operations not being deemed to be included in this proscription).

         (f) Notwithstanding anything to the contrary contained in this
Paragraph 4, Tenant's share of Operating Expenses shall not increase by more
than eight percent (8%) per year (determined cumulatively for the entire term of
this Lease) to the extent attributable to any and all controllable expenses,
i.e., with the limitation expressed in this subsection (f) not being applicable
to uncontrollable expenses such as utilities, taxes and insurance cause the
Operating Expenses to increase by more than eight percent per year.

         5. ELECTRICITY. (a) If Landlord, in its reasonable discretion, believes
that Tenant is consuming substantially more electricity in the Premises than
Landlord, in its reasonable discretion, considers standard for normal office
usage (whether by reason of type of usage, hours of operation, heat generation
or otherwise), Landlord may have an electric power consumption survey conducted
with respect to the Premises by a qualified electrical engineer selected by
Landlord for the purpose of establishing as closely as reasonably possible
Tenant's average monthly consumption of electricity, which consumption shall be
expressed by such engineer in terms of kilowatt hours per month. Tenant agrees
to pay to Landlord within ten (10) days after receipt of any such monthly
statement, the amount, if any, by which (i) the product of the number of
kilowatt hours estimated by such engineer to be consumed by Tenant, multiplied
by the average rate paid by Landlord for one kilowatt hour, exceeds (ii) the
product of the number of kilowatt hours of usage that Landlord considers
standard for normal office usage for the amount of space occupied by Tenant,
multiplied by the average paid by Landlord for one kilowatt hour.



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<PAGE>   7

         (b) Without Landlord's prior written consent, Tenant shall not install
any equipment in the Premises that will require any electrical current or
equipment for its use, other than that supplied by Landlord for normal office
usage, and the cost of special electrical installations approved by Landlord
shall be paid by Tenant.

         6. PAYMENTS AND PERFORMANCE. Tenant agrees to pay all rents and sums
provided to be paid by Tenant pursuant to this Lease at the times and in the
manner herein provided, without any setoff, deduction or counterclaim
whatsoever. Should this Lease commence on a day other than the first day of a
calendar month or terminate on a day other than the last day of a calendar
month, the rent for such partial month shall be proportionately reduced. The
Base Rental for the first partial month, if any, shall be payable at the
beginning of said period or as Prepaid Rental. The obligation of Tenant to pay
rentals is an independent covenant, and no act or circumstance whatsoever,
whether such act or circumstance constitutes a breach of covenant by Landlord or
not, shall release Tenant from the obligation to pay rentals. Time is of the
essence in the performance of all of Tenant's obligations hereunder. In the
event any rental is not received within ten (10) days after its due date for any
reason whatsoever, or if any rental payment is by check which is returned for
insufficient funds, then in addition to the past due amount Tenant shall pay to
Landlord a late charge in an amount equal to two percent (2%) of the rental then
due, in order to compensate Landlord for its administrative and other overhead
expenses. Any such late charge shall be payable on demand as additional rental.
In addition, if rental is paid by a check which is returned for insufficient
funds, Tenant shall immediately make the required payment to Landlord in good
funds; moreover, in such event Tenant shall also pay to Landlord not only the
late charge specified above in this Paragraph 6 (i.e., if and to the extent that
such dishonored check causes the rental to become past due by more than ten
days), but also an additional fee of $50.00 to compensate Landlord for its
expense and effort in connection with the dishonored check.

         7. INSTALLATION OF IMPROVEMENTS; ADA COMPLIANCE. All improvements to be
installed in the Premises at the commencement of this Lease shall be installed
as specified in the Leasehold Improvements Agreement attached hereto as Exhibit
D and made a part hereof. Tenant will assure that the plans and specifications
for its improvements, as well as its business operations within the Premises,
comply with the Americans With Disabilities Act of 1990, as amended, and all
related state and local laws (collectively, the "ADA"); and Landlord agrees that
the remainder of the Building, i.e., other than the Premises, shall be in
compliance with the ADA (taking into account the fact that the Building was
constructed before the effective date of the ADA).

         8. COMPLETION OF IMPROVEMENTS AND COMMENCEMENT OF RENT. If the Premises
are not ready for occupancy by Tenant on the Commencement Date of this Lease,
the obligations of Landlord and Tenant shall nevertheless continue in full force
and effect, including the obligation of Tenant to commence paying rent on the
Commencement Date stated in Paragraph 1(d); provided, however, that if the
Premises are not ready for occupancy for any reason other than Tenant's Delay
(as defined in Exhibit D), then (i) the rent shall abate and not commence until
the date the leasehold improvements to the Premises are substantially complete,
and (ii) the Lease Term shall be extended to be the number of months provided in
Paragraph 1(d) above, i.e., after the Commencement Date, as extended. Any such
abatement of rent, however, shall constitute full settlement of all claims that
Tenant might otherwise have against Landlord by reason of the Premises not being
ready for occupancy by Tenant on the Commencement Date of this Lease.
Notwithstanding the foregoing, if Tenant, with Landlord's consent, occupies the
Premises after substantial completion of Tenant's leasehold improvements but
prior to the beginning of the Lease Term set forth herein, all of the terms and
provisions of this Lease shall be in full force and effect from the commencement
of such occupancy and the Lease Term shall commence on the date on which Tenant
first occupies the Premises and shall expire the same period of months
thereafter as shown in Paragraph 1(d); no change shall occur in the length of
the Lease Term.

         9. LIMITED RIGHT TO CALCULATE RENTABLE SPACE; SUBSEQUENT LIQUIDATION.
(a) Landlord and Tenant agree that at any time within sixty (60) days after the
date of this Lease, Tenant may, at its sole expense, employ a licensed architect
to calculate the Rentable Space of the Premises and/or of the Building. If the
architect performing any such services should issue a written statement within
ninety (90) days after the date of this Lease, which indicates that the Rentable
Space specified for either the Premises or the Building should be modified (a
"MODIFICATION STATEMENT"), and if the other party to this Lease agrees with such
Modification



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Statement, then Landlord and Tenant shall execute a written Amendment to Lease
confirming the mutually agreed information and the appropriate rental adjustment
which results from the corrected information (e.g., increasing or decreasing the
Base Rental proportionate with the increase or decrease in the Rentable Space).
If the architect performing any such services should issue a Modification
Statement within ninety (90) days after the date of this Lease, and if the other
party to this Lease does not agree with such Modification Statement, then the
other party may, at its sole expense, within sixty (60) days after the date of
the Modification Statement, employ a licensed architect to review and respond to
the Modification Statement (the "RESPONSE"). If the two architects fail to reach
agreement within thirty (30) days after the date of the Response, then they
shall select a third licensed architect (either by agreement between the two
architects or, if they fail to agree on the third architect, by requesting that
the Dallas chapter of the American Institute of Architects provide the third
architect), with the fees of the third architect to be shared equally by
Landlord and Tenant. Upon agreement between the two architects selected by the
parties, or upon the final decision of the third architect, Landlord and Tenant
shall execute a written Amendment to Lease confirming the final determination
and, if necessary, the appropriate rental adjustment.

         (b) Notwithstanding anything contained in this Lease to the contrary,
both Landlord and Tenant acknowledge and confirm their mutual desire to have all
financial obligations under this Lease fixed and liquidated as soon as possible
so that they can account for and plan such obligations with greater certainty.
Accordingly, the parties agree that if neither party employs a licensed
architect to perform any of the above-listed services within sixty (60) days
after the date of this Lease, or if no Modification Statement is delivered
within ninety (90) days after the date of this Lease, then the provisions of
Paragraph 9(a) shall be null and void and of no further force or effect; and in
such event (i) so that both parties to this Lease can be assured that they will
not have to expend monies for professional fees regarding Rentable Space
determinations after the deadlines established in Paragraph 9(a), they hereby
agree that the Rentable Space for the Premises and for the Building, as
specified in Paragraph 1(c) above, shall conclusively be deemed to be applicable
to this Lease; and (ii) so that both parties to this Lease can be assured as to
their financial obligations after the deadlines established in Paragraph 9(a),
they further agree that Base Rental, the Allowance, rental adjustments and all
other aspects of this Lease which are based in whole or in part upon Rentable
Space shall be deemed to be liquidated and no longer subject to adjustment based
upon inaccuracies and/or errors, if any, in the Rentable Space determinations
specified in Paragraph 1(c).

         10. REPAIRS AND REENTRY. Tenant will, at Tenant's own cost and expense,
maintain and keep the Premises and any alterations and additions thereto in
sound condition and good repair, and shall pay for the repair of any damage or
injury done to the Building or any part thereof by Tenant or Tenant's agents,
employees and invitees; provided, however, that Tenant shall make no repairs to
the Premises without the prior written consent of Landlord which shall not be
unreasonably withheld or delayed. The performance by Tenant of its obligation to
maintain and make repairs shall be conducted only by contractors approved by
Landlord after plans and specifications have been approved by Landlord. Tenant
will not commit or allow any waste or damage to be committed on any portion of
the Premises, and upon the termination of this Lease by lapse of time or
otherwise, Tenant shall deliver up the Premises to Landlord in as good condition
as at date of possession, ordinary wear and tear excepted. Upon such termination
of this Lease, Landlord shall have the right to reenter and resume possession of
the Premises. Notwithstanding the foregoing provisions of this Paragraph 10, any
repairs to the Premises or the Building that are necessitated because of any
damage caused by fire or other casualty shall be governed by the provisions of
Paragraph 18 below. Landlord shall be responsible for maintenance to the
exterior, structural and common areas of the Building.

         11. ALTERATIONS AND ADDITIONS BY TENANT. Tenant shall make no
alterations in or additions to the Premises without the prior written consent of
Landlord; and all alterations, additions, and improvements made to or fixtures
or improvements placed in or upon the Premises by either party (except only
moveable trade fixtures of Tenant) shall be deemed a part of the Building and
the property of the Landlord at the time they are placed in or upon the
Premises, and they shall remain upon and be surrendered with the Premises as a
part thereof at the termination of this Lease, unless Landlord shall elect
otherwise, whether such termination shall occur by the lapse of time or
otherwise. In the event Landlord shall elect that certain alterations, additions
and improvements made by Tenant in the Premises shall be removed by Tenant,
Tenant shall remove them and Tenant shall restore the Premises to its original
condition,



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<PAGE>   9

at Tenant's own cost and expense, prior to the termination of the Lease Term.
Alterations and additions to the Premises will be performed by Landlord at
Tenant's cost and expense.

         12. ENTRY BY LANDLORD. Landlord and its agents and representatives
shall have the right to enter into and upon any and all parts of the Premises at
all reasonable hours and upon 24 hours notice (or, in any emergency, at any
hour) to inspect same, to clean or make repairs or alterations or additions as
Landlord may deem necessary, and to obtain access to mechanical rooms and other
Building facilities (including, without limitation, the roof if the Premises
includes the top floor of the Building); and Tenant shall not be entitled to any
abatement or reduction of rent by reason thereof. During the period of 180 days
prior to the expiration date of this Lease, Landlord and Landlord's agents may
exhibit the Premises to prospective tenants at reasonable hours and upon 24
hours prior notice to Tenant.

         13. MECHANIC'S LIENS. Nothing contained in this Lease shall authorize
Tenant to do any act which shall in any way encumber the title of Landlord in
and to the Premises or the Building or any part thereof; and if any mechanic's
or materialman's lien is filed or claimed against the Premises or Building or
any part thereof in connection with any work performed, materials furnished or
obligation incurred by or at the request of Tenant, Tenant will promptly pay
same or cause it to be released of record. If the lien is not released of record
and default in payment thereof shall continue for twenty (20) days after written
notice thereof from Landlord to Tenant, Landlord shall have the right and
privilege at Landlord's option of paying the same or any portion thereof without
inquiry as to the validity thereof, and any amounts so paid, including expenses
and interest, shall be repaid to Landlord immediately on demand therefor.

         14. TENANT'S USE. Tenant will be solely responsible for obtaining all
necessary certificates (e.g., Certificate of Occupancy) and licenses necessary
for Tenant's occupancy of the Premises and conducting its business therein.
Tenant will not occupy or use any portion of the Premises for any purpose other
than the Sole Permitted Use or for any purpose which is unlawful or which, in
the good faith judgment of Landlord, is disreputable or which is hazardous due
to risk of fire, explosion or other casualty, nor permit anything to be done
which will in any way (i) increase the rate of fire and casualty insurance on
the Building or its contents, or (ii) tend to lower the first-class character of
the Building, or (iii) create unreasonable elevator loads or otherwise interfere
with standard building operations, or (iv) affect the structural integrity or
design capabilities of the Building or any portion thereof (e.g., a floor being
occupied by Tenant). In the event that, by reason of any act or conduct or
business of Tenant, there shall be any increase in the rate of insurance on the
Building or its contents created by Tenant's acts or conduct or business, then
Tenant hereby agrees to pay Landlord the amount of such increase on demand.
Tenant will conduct its business, and control its agents, employees, and
invitees in such a manner as not to create any nuisance or interfere with, annoy
or disturb other tenants or Landlord in the management of the Building.

         15. LAWS AND REGULATIONS; RULES OF THE BUILDING. (a) Tenant at its sole
expense will maintain the Premises in a clean and healthful condition and will
comply with all laws, ordinances, orders, rules and regulations of any
governmental authority having jurisdiction over the use, conditions or occupancy
of the Premises. Without limiting the generality of the foregoing, Tenant shall
comply strictly and in all respects with the requirements of all Hazardous Waste
Laws and shall indemnify Landlord and hold Landlord harmless from and against
any liability, costs or expenses that may arise on account of the release,
discharge, storage, disposal, treatment, processing or other handling or
discovery of any Hazardous Substance within the Premises, or the discharge,
release, disposal, storage, treatment, processing or other handling of any
Hazardous Substance by Tenant, its employees, agents, contractors, or invitees
anywhere on the Land or within the Building, or off site. As used herein,
"HAZARDOUS SUBSTANCE" means any substance, material or matter that may give rise
to liability under any Hazardous Waste Laws, including (but not limited to)
medical waste and petroleum products or petroleum wastes. "HAZARDOUS WASTE LAWS"
shall mean any local, state or federal laws, rules, ordinances, regulations, and
policy and guidance statements by the Environmental Agencies, either in
existence as of the date hereof, or enacted, promulgated or issued after the
date of this Lease, that concern the management, control, discharge, treatment,
containment or removal of substances or materials that are or may become a
threat to public health or the environment.

         (b) Tenant and Tenant's agents, employees, and invitees will comply
fully with all Rules and Regulations of the Building which are attached hereto
as Exhibit E and made a part hereof as though fully set out herein. As more
particularly provided therein, Landlord shall at all



                                       9
<PAGE>   10

times have the right to change such rules and regulations or to amend them in
such reasonable manner as may be deemed advisable for the safety, protection,
care and cleanliness of the Building and appurtenances and for preservation of
good order therein, all of which rules and regulations, changes and amendments
will be forwarded to Tenant in writing and shall be complied with and observed
by Tenant; provided, however, that no new rules or regulations shall deprive
Tenant of any rights expressly granted to Tenant pursuant to this Lease.

         16. INDEMNITY, LIABILITY AND LOSS OR DAMAGE. By moving into the
Premises or taking possession thereof, Tenant accepts the Premises as suitable
for the purposes for which they are leased and accepts the Building and each and
every appurtenance thereof, and waives any and all defects therein (with the
exception of latent defects). Landlord shall not be liable to Tenant or Tenant's
agents, employees, guests, invitees or any person claiming by, through or under
Tenant for any injury to person, loss of or damage to property, or for loss of
or damage to Tenant's business, occasioned by or through the acts or omissions
of Landlord, or by any cause whatsoever except Landlord's gross negligence or
willful wrongdoing. Unless arising from or out of Landlord's gross negligence or
willful wrongdoing, Landlord shall not be liable for, and Tenant shall indemnify
Landlord and save it harmless from, all suits, actions, damages, liability and
expense in connection with loss of life, bodily or personal injury or property
damage arising from or out of any occurrence in, upon, at or from the Premises
or the occupancy or use by Tenant of the Premises or any part thereof, or
occasioned wholly or in part by any action or omission of Tenant, its agents,
contractors, employees, invitees, or licensees. If Landlord shall, without fault
on its part, be made a party to any action commenced by or against Tenant,
Tenant shall protect and hold Landlord harmless therefrom and shall pay all
costs, expenses, and reasonable attorney's fees to Landlord incurred in
connection therewith.

         (b) Tenant shall not be liable to Landlord or Landlord's agents,
employees, guests, invitees or any person claiming by, through or under Landlord
for any injury to person, loss of or damage to property, or for loss of or
damage to Landlord's business, occasioned by or through the acts or omissions of
Tenant, its agents, contractors or employees. Except to the extent arising from
or out of Tenant's negligence or willful wrongdoing, Tenant shall not be liable
for, and Landlord shall indemnify Tenant and save it harmless from, all suites,
actions, damages, liability and expense in connection with loss of life, bodily
or personal injury or property damage arising from or out of any occurrence in,
upon, at or from the Building (with the exception of the Premises) or the
occupancy or use by Landlord of the Building or any part thereof (i.e., other
than the Premises), or occasioned wholly or in part by any action or omission of
Landlord, its agents, contractors or employees. If Tenant shall, without fault
on its part, by made a party to any action commenced by or against Landlord, the
subject of which is covered by the immediately foregoing indemnity, Landlord
shall protect and hold Tenant harmless therefrom and shall pay all costs,
expenses, and reasonable attorney's fees to Tenant incurred in connection
therewith.

         (c) This Paragraph 16 is subject to Paragraph 17 below.

         17. NO SUBROGATION; INSURANCE. (a) Tenant hereby waives any cause of
action it might have against Landlord on account of any loss or damage that is
insured against under any insurance policy that covers the Premises, Tenant's
fixtures, personal property, leasehold improvements or business and which names
Tenant as a party insured. Landlord hereby waives any cause of action it might
have against Tenant because of any loss or damage that is insured against under
any insurance policy that covers the Building or any property of Landlord used
in connection with the Building and which names Landlord as a party insured,
provided that if the cost of restoring the loss or damage exceeds the amount of
property damage insurance proceeds paid to Landlord on account of the loss or
damage, Tenant shall remain liable to Landlord for the amount of such excess.
This provision is cumulative of Paragraph 16.

         (b) Tenant shall procure and maintain throughout the term of this Lease
a policy or policies of insurance, at its sole cost and expense, insuring Tenant
and Landlord against any and all liability for injury to or death of a person or
persons, occasioned by or arising out of or in connection with the use or
occupancy of the Premises as follows:

                  (1)      FIRE INSURANCE, including extended coverage,
                           vandalism and malicious mischief, and demolition and
                           debris removal, insuring for an amount no less than



                                       10
<PAGE>   11

                           80% of the current replacement cost of all Tenant
                           improvements, alterations or additions made to the
                           Premises by Landlord for Tenant, and Tenant's trade
                           fixtures, inventory, furniture and equipment owned,
                           controlled or in use by Tenant and situated in the
                           Premises. Landlord shall have no interest in the
                           insurance upon Tenant's equipment and fixtures and
                           will sign all documents necessary in the settlement
                           of any claim. Landlord will not carry insurance of
                           Tenant's property or improvements to the Premises
                           made by Tenant.

                  (2)      COMMERCIAL GENERAL LIABILITY INSURANCE including
                           Bodily Injury and Property Damage Liability and
                           Personal Advertising Injury Liability on an
                           occurrence basis with respect to Tenant's business
                           and occupancy of the Premises for any one occurrence
                           or claim of not less than $1,000,000 with $1,000,000
                           Products Aggregate and $1,000,000 General Aggregate
                           or such greater amount as Landlord may reasonably
                           require in writing from time to time. Such insurance
                           shall contain a provision including coverage for all
                           liabilities assumed by Tenant under this Lease and
                           shall name Landlord as Additional Insurance.

                  (3)      BUSINESS INTERRUPTION INSURANCE in an amount
                           sufficient to reimburse Tenant for direct or indirect
                           loss of earnings attributable to perils commonly
                           insured against by prudent tenants or attributable to
                           prevention of access to the Building or Premises as a
                           result of such perils.

                  (4)      INSURANCE against such other perils and in such
                           amounts as Landlord may from time to time reasonably
                           require in writing. Such request shall be made on the
                           basis that the insurance coverage requested is
                           customary at the time for prudent tenants.

                  (5)      Tenant shall provide Landlord with an original
                           certificate of insurance upon execution of the lease.

         18. FIRE AND CASUALTY. (a) If the Premises are damaged by fire or other
casualty and if such damage is not susceptible of repair within 150 days (as
estimated, as soon as reasonably practicable after the occurrence of such
damage, by an architect of recognized good reputation selected by Landlord),
then in such event this Lease, at the option of Landlord exercised by giving
written notice thereof to Tenant within 30 days after receipt of a certificate
of the architect so selected, shall terminate as of the date of such loss, and
Tenant shall pay the rent hereunder apportioned to the time of such loss and
shall pay all other obligations of Tenant owing on the date of termination, and
Tenant shall immediately surrender the Premises to Landlord.

         (b) If the damage described above is susceptible of repair within 180
days, or if the damage is not susceptible of repair within 150 days but Landlord
fails to exercise its option to terminate this Lease, Landlord shall enter and
make the necessary repairs without affecting this Lease, but the rent hereunder
shall be reduced or abated as shall be equitable, in the good faith judgment of
Landlord, until such repairs are made, unless such damage has been so slight
that Tenant's occupancy of the Premises is not materially interfered with, in
which case the rent hereunder shall not be abated or reduced. Notwithstanding
the foregoing, Landlord shall have the option to terminate this Lease and shall
not be obligated to repair the Premises or the Building if the damage is not
covered by insurance or if Landlord's mortgagee applies any portion of the
insurance proceeds to the unpaid balance of its loan.

         (c) In the event the Building is so badly damaged or injured by fire or
other casualty, even though the Premises may not be affected, that Landlord
decides, within 90 days after such destruction, not to rebuild or repair the
Building (such decision being vested exclusively in the discretion of Landlord),
then in such event Landlord shall so notify Tenant in writing and this Lease
shall terminate as of the date of such loss, and the Tenant shall pay rent
hereunder apportioned to the date of such loss and shall pay all other
obligations of Tenant owing on the date of termination, and Tenant shall
immediately surrender the Premises to Landlord.

         (d) Notwithstanding the foregoing provisions of this Paragraph 18,
Tenant agrees that if the Premises or any other portion of the Building is
damaged by fire or other casualty resulting from the fault or gross negligence
of Tenant or any of its agents, employees, or invitees, then the



                                       11
<PAGE>   12

cost of restoring the damage in excess of any property damage insurance proceeds
paid to Landlord shall be repaired at the sole cost and expense of Tenant, and
there shall be no abatement of rent before or during the repair of such damage.

         19. CONDEMNATION. If all of the Premises, or so much thereof as would
materially interfere with Tenant's use of the remainder, shall be taken or
condemned for any public use or purpose by right of eminent domain, with or
without litigation, or be transferred by agreement in connection with or in lieu
of or under threat of condemnation, then the term of this Lease and the
leasehold estate created hereby shall terminate as of the date title shall vest
in the condemnor or transferee. If only a portion of the Building, but not the
Premises, is taken or condemned or transferred as aforesaid, Landlord shall have
the option to terminate this Lease effective as of the date title shall vest in
the condemnor or transferee. Landlord shall receive the entire award from any
taking or condemnation (or the entire compensation paid because of any transfer
by agreement), and Tenant shall have no claim thereto.

         20. Intentionally Deleted.

         21. ASSIGNMENT AND SUBLETTING. (a) In the event that Tenant desires to
assign or mortgage this Lease or sublet all or any part of the Premises (with
the term "sublet" being deemed, for purposes of this Paragraph 21, to include
Tenant's grant of a license, concession or other right of occupancy of any
portion of the Premises), Tenant shall notify Landlord in writing (a "PROPOSAL
NOTICE") and shall state in the Proposal Notice the name of the proposed
assignee, mortgagee or sublessee and the terms of the proposed assignment,
mortgage or sublease. In the Proposal Notice Tenant shall also provide financial
information and state the nature and character of the business of the proposed
assignee, mortgage or sublessee. Notwithstanding such Proposal Notice to
Landlord, Tenant shall not assign or mortgage this Lease or any right hereunder
or interest herein, and Tenant shall not sublet the Premises in whole or in part
or grant any license, concession or other right of occupancy of any portion of
the Premises, without the prior written consent of Landlord (which, subject to
subsections (b) and (c) below, shall not be unreasonably withheld). Any such
assignment, mortgage or subletting without Landlord's consent shall be void and
shall, at the sole option of the Landlord, be deemed a breach of this Lease.
Notwithstanding any assignment, mortgage or subletting consented to by Landlord,
Tenant and each assignee shall at all times remain fully responsible and liable
for the payment of the rent herein specified and for compliance with all of
Tenant's other covenants and obligations under this Lease. No consent to any
assignment or mortgage of this Lease or any subletting of the Premises shall
constitute a waiver of the provisions of this paragraph except as to the
specific instance covered thereby. If Tenant is a corporation or partnership, an
assignment prohibited by this Paragraph 21 shall be deemed to include one or
more sales or transfers, by operation of law or otherwise, or creation of new
stock or partnership interests, by which a majority of the voting shares of the
corporation or interests in the partnership shall be vested in a party or
parties who are not owners of a majority of the voting shares or partnership
interests of Tenant as of the date hereof; provided, however, that the foregoing
provisions of this sentence shall not be applicable if Tenant's stock is listed
on a recognized security exchange. Any transfer by operation of law shall also
constitute an assignment prohibited by this Paragraph 21. Unless Landlord's
withholding of consent is attributable primarily to a malicious intent to injure
Tenant (i.e., as opposed to a difference of opinion between Landlord and
Tenant), Landlord shall not be liable to Tenant for wrongfully withholding its
consent to an assignment or subletting under this Lease and Tenant's sole remedy
on account thereof shall be to enforce specific performance of Landlord's
obligation to consent.

         (b) Landlord and Tenant hereby agree that the granting of consent by
Landlord (i.e., if such consent is granted) shall, at a minimum, be
preconditioned upon the fulfillment of the following requirements of Landlord,
as well as any other reasonable requirements of Landlord:

                  (1) Landlord shall be entitled to review Tenant's Proposal
         Notice for at least twenty (20) days after receiving same from Tenant;

                  (2) Tenant shall remain primarily liable under this Lease and
         shall guaranty the Lease if Landlord so requests;

                  (3) Any proposed assignee or sublessee shall assume, in a
         written instrument acceptable to Landlord, all of the obligations of
         Tenant hereunder;



                                       12
<PAGE>   13

                  (4) No use shall be employed in connection with the Premises
         other than the Sole Permitted Use set forth in this Lease;

                  (5) The Premises shall remain intact and shall not be altered
         in any manner whatsoever unless Tenant and the prospective assignee or
         sublessee shall pay the entire cost thereof, and Landlord's prior
         written approval is obtained pursuant to Paragraph 10 above;

                  (6) The tangible net worth of the proposed subtenant/assignee
         must be reasonably sufficient for the obligations under this Lease;

                  (7) Any use of the Premises permitted hereunder by the
         proposed sublessee/assignee must not (i) violate or create any
         potential violation of any laws, nor (ii) violate any other agreements
         affecting the Premises, the Building or Landlord, nor (iii) increase by
         more than 5% the density of employees and/or other persons using the
         Premises from the density maintained by Tenant;

                  (8) The proposed subtenant/assignee will not create traffic
         congestion or an unreasonable burden on existing parking or elevators;

                  (9) Tenant shall pay any and all reasonable attorney's fees or
         other costs associated with Landlord's review and approval of a
         prospective assignee or sublessee, not to exceed $200.00;

                  (10) No assignment or sublease shall be to a person or entity
         with whom Landlord is then negotiating, has negotiated with within the
         previous six months or currently is a tenant within the Building.

         (c) Notwithstanding anything contained above in this Paragraph 21,
Tenant agrees that after Landlord receives a Proposal Notice from Tenant, then
in addition to the rights granted to Landlord in subsections (a) and (b)
immediately above and if Tenant is proposing to sublet more than 70% of the
space, Landlord shall also be entitled to terminate this Lease; moreover, in the
event of a proposed sublease, Landlord shall also be entitled either to
terminate this Lease as to only the subject of the sublease (with all remaining
portions of the Premises to remain subject to this Lease, prorated as
appropriate to account for a smaller Premises), or, as a further option, to
become Tenant's subtenant under the same terms and conditions as were set forth
in the Proposal Notice. The options granted to Landlord pursuant to this
subsection (c) are cumulative with the rights granted to Landlord pursuant to
subsections (a) and (b) of this Paragraph 21.

         (d) In the event of a sublease approved by Landlord where the monthly
rental per square foot of space subleased which is payable by any sublessee to
Tenant (including any bonuses or any other consideration paid directly or
indirectly by the sublessee to Tenant) exceeds the monthly rental per square
foot for the same space payable for the same month by Tenant to Landlord, Tenant
shall be obligated to pay fifty percent (50%) of the amount of such excess to
Landlord as additional rent hereunder within twenty (20) days after it is
received by Tenant from the sublessee. In the event of an assignment approved by
Landlord where Tenant receives any consideration from an assignee other than the
assumption by the assignee of Tenant's obligations hereunder, Tenant shall be
obligated to pay the amount of such consideration to Landlord as additional rent
hereunder within twenty (20) days after the date it is received by Tenant.
Landlord, at Landlord's option, may elect to require that rental payable by any
sublessee be paid directly to Landlord and offset Tenant's rent obligations
accordingly.

         22. HOLDING OVER. Should Tenant continue to hold the Premises after
this Lease terminates, whether by lapse of time or otherwise, such holding over
shall, unless otherwise agreed by Landlord in writing, constitute and be
construed as a tenancy at will at a daily rental equal to one-thirtieth (1/30)
of an amount equal to 150% of the amount of the monthly rental payable during
the last month prior to the termination of this Lease, and upon and subject to
all of the other terms and provisions set forth herein except any right to renew
this Lease. This provision shall not be construed, however, as permission by
Landlord for Tenant to hold over.



                                       13
<PAGE>   14

         23. ABANDONED PROPERTY. All personal property of Tenant remaining in
the Premises after the expiration of the Lease Term or after the abandonment of
the Premises by Tenant may be treated by Landlord as having been abandoned by
Tenant, and Landlord shall have the right to remove such personal property from
the Premises without any obligation to deliver such personal property to Tenant
and without any liability to Tenant whatsoever, it being agreed that Tenant
shall have no right to reclaim such property. Landlord shall have no duty to
notify Tenant that Landlord may dispose of Tenant's property. Tenant shall be
presumed conclusively to have abandoned the Premises if the amount of Tenant's
property removed or being removed by Tenant from the Premises is substantial
enough to indicate a probable intent to abandon the Premises, and such removal
is not within the normal course of Tenant's business, or if Tenant removes or is
removing any material amount of Tenant's personal property from the Premises at
a time when Tenant is in default in the payment of rental due hereunder and such
removal is not within the normal course of Tenant's business. Nothing contained
in this paragraph shall prejudice or impair Landlord's rights as a lienholder
and secured party under Paragraph 28 hereof, and the rights granted to Landlord
under this paragraph shall be cumulative of its rights as a lienholder and
secured party.

         24. TAXES. (a) Tenant shall be liable for all taxes levied or assessed
against all personal property, furniture and fixtures placed by Tenant, or on
Tenant's behalf, in the Premises. If any such taxes for which Tenant is liable
are levied or assessed against Landlord or Landlord's property and if Landlord
elects to pay the same or if the assessed value of Landlord's property is
increased by inclusion of personal property, furniture or fixtures placed by
Tenant in the Premises, and Landlord elects to pay the taxes based on such
increase, Tenant shall pay Landlord upon demand that part of such taxes for
which Tenant is primarily liable hereunder.

         (b) Tenant agrees that, as between Tenant and Landlord, Landlord has
the sole and absolute right to contest taxes levied against the Premises and the
Building (other than taxes levied directly against Tenant's personal property
within the Premises). Accordingly, Tenant, to the maximum extent permitted by
law, irrevocably waives any and all rights that Tenant may have to receive from
Landlord a copy of notices received by Landlord regarding the appraisal or
reappraisal, for tax purposes, of all or any portion of the Premises or the
Building (including, without limitation, any rights set forth in ss.41.413 of
the Texas Property Tax Code, as such section may be amended and/or supplemented
from time to time). Additionally, Tenant, to the maximum extent permitted by
law, hereby assigns to Landlord any and all rights of Tenant to protest or
appeal any governmental appraisal or reappraisal of the value of all or any
portion of the Premises or the Building (including, without limitation, any
rights set forth in ss.41.413 and ss.42.015 of the Texas Property Tax Code, as
such sections may be amended and/or supplemented from time to time). To the
maximum extent permitted by law, Tenant agrees that it will not protest or
appeal any such appraisal or reappraisal before a governmental taxing authority
without the express written authorization of Landlord.

         25. TRANSFER OF LANDLORD'S RIGHTS. In the event Landlord transfers its
interest in the Building, Landlord shall thereby be released from any further
obligations hereunder, and Tenant agrees to look solely to the successor in
interest of the Landlord for the performance of such obligations.

         26. DEFAULT. (a) The following events shall be deemed to be events of
default by Tenant under this Lease: (i) Tenant shall fail to pay any rental or
other sums payable by Tenant hereunder as and when such rental or other sums
become due and payable and any such failure shall continue for a period of ten
(10) days after written notice from Landlord to Tenant (provided, however, that
if in any calendar year Landlord has given at least two written notices of
rental defaults to Tenant, then for the remainder of that particular calendar
year the grace period shall be reduced to five days and there shall be no
requirement of written notice from Landlord to Tenant); (ii) Tenant shall fail
to comply with any other provision, condition or covenant of this Lease and any
such failure shall continue for a period of thirty (30) days after Landlord
gives written notice thereof to Tenant; (iii) Tenant shall abandon, vacate or
fail to physically occupy any substantial portion of the Premises; (iv) any
petition shall be filed by or against Tenant or any guarantor of Tenant's
obligations under this Lease pursuant to any section or chapter of the present
federal Bankruptcy Act or under any future federal Bankruptcy Act or under any
similar law or statute of the United States or any state thereof, or Tenant or
any



                                       14
<PAGE>   15

guarantor of Tenant's obligations under this Lease shall be adjudged bankrupt or
insolvent in proceedings filed under any section or chapter of the present
federal bankruptcy act or under any future federal bankruptcy act or under any
similar law or statute of the United States or any state thereof; (v) Tenant or
any guarantor of Tenant's obligations under this Lease shall become insolvent or
make a transfer in fraud of creditors; (vi) Tenant or any guarantor of this
Lease shall make an assignment for the benefit of creditors; or (vii) a receiver
or trustee shall be appointed for Tenant or any of the assets of Tenant.

         (b) Upon the occurrence of any event of default, Landlord shall have
the option to do any one or more of the following WITHOUT ANY FURTHER NOTICE OR
DEMAND, in addition to and not in limitation of any other remedy permitted by
law or by this Lease:

         (1)      Landlord may enforce, by all legal suits and other means, its
                  rights hereunder, including the collection of Base Rental and
                  any other sums payable by Tenant hereunder, without reentering
                  or resuming possession of Premises and without terminating
                  this Lease.

         (2)      Landlord may do whatever Tenant is obligated to do by the
                  provisions of this Lease; and to the extent that Landlord
                  deems it necessary or otherwise appropriate for Landlord to
                  enter the Premises, Landlord may enter the Premises, by force
                  if necessary (but only if and to the extent permitted by law),
                  in order to accomplish this purpose. Tenant hereby waives any
                  and all claims for damages caused by Landlord's actions
                  pursuant to this subparagraph (b)(2), and Tenant also agrees
                  to reimburse Landlord immediately upon demand for any expenses
                  which Landlord may incur in thus effecting compliance with
                  this Lease on behalf of Tenant.

         (3)      If (but only if) Tenant is in arrears in its rentals by more
                  than one month, Landlord may enter upon and take possession of
                  the Premises without terminating this Lease and expel or
                  remove Tenant and its effects therefrom without being liable
                  to prosecution of any claims for damages therefor, and
                  Landlord may relet the Premises for the account of Tenant.
                  Tenant shall pay to Landlord all arrearages of Base Rental and
                  other sums due and owing by Tenant to Landlord, and Tenant
                  shall also pay to Landlord during each month of the unexpired
                  Lease Term the installments of Base Rental and other sums due
                  hereunder, less such part, if any, that Landlord shall have
                  been able to collect from a new tenant upon reletting. In this
                  regard the parties further agree that although Landlord shall
                  use its reasonable efforts to relet the Premises after Tenant
                  has vacated the Premises, Landlord shall have no obligation to
                  agree to any lease terms which it deems to be unacceptable,
                  nor shall Landlord be obligated (i) to travel outside a radius
                  of thirty (30) miles from its principal office in order to
                  meet with a prospective tenant, (ii) to accept a prospective
                  tenant for the Premises (or any portion thereof) which is an
                  existing or prospective tenant elsewhere in the Building, or
                  (iii) to expend monies for finish-out requested by a
                  prospective tenant unless Landlord, in its sole and absolute
                  discretion, approves both the lease terms and the credit of
                  such prospective tenant. Tenant further agrees that in the
                  event of any reletting, Tenant shall pay to Landlord on demand
                  all Reimbursable Costs prescribed in the final portion of this
                  Paragraph 26. In the event Landlord exercises the rights and
                  remedies afforded to it under this Paragraph 26(b)(3) and then
                  subsequently elects to terminate this Lease, Tenant shall be
                  liable to Landlord for damages as set forth in the final two
                  sentences of Paragraph 26(b)(5) below and Landlord shall have
                  the right at any time to demand final settlement as provided
                  therein.


         (4)      If (but only if) Tenant is in arrears in its rentals by more
                  than one month, Landlord may enter upon the Premises by use of
                  a duplicate key, a master key, an electronic pass card, a
                  locksmith's entry procedures or any other means not involving
                  personal confrontation, and change, alter or modify the door
                  locks on all entry doors of the Premises, thereby excluding
                  Tenant and its agents, employees, representatives and
                  invitees, from the Premises. In such event Landlord shall not
                  be obligated to place any written notice on the Premises
                  explaining Landlord's action; moreover, Landlord shall not be
                  required to provide the new key (if any) to Tenant until and
                  unless all rental defaults of Tenant have been fully cured.



                                       15
<PAGE>   16

         (5)      If (but only if) Tenant is in arrears in its rentals by more
                  than one month, Landlord may terminate this Lease, in which
                  event Tenant shall immediately surrender the Premises to
                  Landlord, but if Tenant shall fail to do so, Landlord may
                  without notice and without prejudice to any other remedy
                  Landlord may have, enter upon and take possession of the
                  Premises and expel or remove Tenant and its effects without
                  being liable to prosecution or any claim for damages therefor;
                  and upon any such termination, Tenant agrees that in addition
                  to its liability for the payment of arrearages of Base Rental
                  and other sums due and owing by Tenant to Landlord under this
                  Lease upon such termination, Tenant shall be liable to
                  Landlord for damages. Tenant shall pay to Landlord as damages
                  on the same days as Base Rental and other payments are
                  expressed to be due under the provisions of this Lease, the
                  total amount of such Base Rental and other payments, less such
                  part, if any, of such payments that Landlord shall have been
                  able to collect from a new tenant upon reletting. In this
                  regard the parties further agree that although Landlord shall
                  use its reasonable effort to relet the Premises after Tenant
                  has vacated the Premises, Landlord shall have no obligation to
                  agree to any lease terms which it deems to be unacceptable,
                  nor shall Landlord be obligated (i) to travel outside a radius
                  of thirty (30) miles from its principal office in order to
                  meet with a prospective tenant, (ii) to accept a prospective
                  tenant for the Premises (or any portion thereof) which is an
                  existing or prospective tenant elsewhere in the Building, or
                  (iii) to expend monies for finish-out requested by a
                  prospective tenant unless Landlord, in its sole and absolute
                  discretion, approves both the lease terms and the credit of
                  such prospective tenant. Tenant further agrees that in the
                  event of any reletting, Tenant shall pay to Landlord on demand
                  all Reimbursable Costs prescribed in the final portion of this
                  Paragraph 26. Landlord shall have the right at any time to
                  demand final settlement. Upon demand for a final settlement,
                  Landlord shall have the right to receive, and Tenant hereby
                  agrees to pay, as damages for Tenant's breach and in addition
                  to the Reimbursable Costs prescribed in the final section of
                  this Paragraph 26, the difference between the total rental
                  provided for in this Lease for the remainder of the Lease Term
                  and the reasonable rental value of the Premises for such
                  period, such difference to be discounted to present value at a
                  rate equal to the rate of interest allowed by law (at the time
                  the demand for final settlement is made) when the parties to a
                  contract have not agreed on any particular rate of interest
                  (or, in the absence of such law, at the rate of 6% per annum).

Pursuit of any of the foregoing remedies shall not preclude pursuit of any of
the other remedies herein provided or any other remedies provided by law or
equity. Any entry by Landlord upon the Premises may be by use of a master or
duplicate key or electronic pass card or any locksmith's entry procedure or
other peaceable means. Any reletting by Landlord shall be without notice to
Tenant, and if Landlord has not terminated this Lease, the reletting may be in
the name of Tenant or Landlord, as Landlord shall elect. Any reletting shall be
for such term or terms (which may be greater or less than the period which
constitutes the balance of the Lease Term) and on such terms and conditions
(which may include free rent, rental concessions or tenant inducements of any
nature) as Landlord in its absolute discretion may determine, and Landlord may
collect and receive any rents payable by reason of such reletting. In the event
any rentals actually collected by Landlord upon any such reletting for any
calendar month are in excess of the amount of rental payable by Tenant under
this Lease for the same calendar month, the amount of such excess shall belong
solely to Landlord, and Tenant shall have no right with respect thereto (except,
however, same shall be applied to Tenant's deficiency, if any). In the event it
is necessary for Landlord to institute suit against Tenant in order to collect
the rental or any other sum due hereunder or any deficiency between the rental
and any other sum provided for by this Lease for a calendar month and the rental
and any other sum actually collected by Landlord for such calendar month,
Landlord shall have the right to allow such deficiency to accumulate and to
bring an action upon several or all of such rental deficiencies at one time. Any
suit shall not prejudice in any way the right of Landlord to bring a similar
action for any subsequent rental deficiency or deficiencies.

         27. SECURITY DEPOSIT. The Security Deposit shall be held by Landlord
without liability for interest and as security for the performance by Tenant of
Tenant's covenants and



                                       16
<PAGE>   17

obligations under this Lease, it being expressly understood that the Security
Deposit shall not be considered an advance payment of rental or a measure of
Landlord's damages in case of default by Tenant upon the occurrence of any event
of default by Tenant or upon termination of this Lease. Landlord may commingle
the Security Deposit with Landlord's other funds. Landlord may, from time to
time, without prejudice to any other remedy, use the Security Deposit to the
extent necessary to make good any arrearages of rent or to satisfy any other
covenant or obligation of Tenant hereunder. Following any such application of
the Security Deposit, Tenant shall pay to Landlord on demand the amount so
applied in order to restore the Security Deposit to its original amount. If
Tenant is not in default at the termination of this Lease, the balance of the
Security Deposit remaining after any such application shall be returned by
Landlord to Tenant. If Landlord transfers its interest in the Premises during
the term of this Lease, Landlord may assign the Security Deposit to the
transferee and thereafter shall have no further liability for the return of such
Security Deposit.

         28. Intentionally Deleted.

         29. REMEDIES. No act or thing done by Landlord or its agents during the
term hereof shall be deemed an acceptance of an attempted surrender of the
Premises, and no agreement to accept a surrender of the Premises shall be valid
unless made in writing and signed by Landlord. No reentry or taking possession
of the Premises by Landlord shall be construed as an election on its part to
terminate this Lease, unless a written notice of such intention is given to
Tenant. Notwithstanding any such reletting or reentry or taking possession,
Landlord may at any time thereafter elect to terminate this Lease for a previous
default. Landlord's acceptance of rent following an event of default hereunder
shall not be construed as Landlord's waiver of such event of default. No waiver
by Landlord of any violation or breach of any of the terms, provisions and
covenants herein contained shall be deemed or construed to constitute a waiver
of any other violation or breach of any of the terms, provisions and covenants
herein contained. Forbearance by Landlord to enforce one or more of the remedies
herein provided upon an event of default shall not be deemed or construed to
constitute a waiver of any other violation or default. The failure of Landlord
to enforce the rules described in Paragraph 15 against Tenant or any other
tenant in the Building shall not be deemed a waiver of any such rules. No
provisions of this Lease shall be deemed to have been waived by Landlord unless
such waiver is in writing and is signed by Landlord. The rights granted to
Landlord in this Lease shall be cumulative of every other right or remedy which
Landlord may otherwise have at law or in equity, and the exercise of one or more
rights or remedies shall not prejudice or impair the concurrent or subsequent
exercise of other rights or remedies. If Landlord brings any action under this
Lease, or consults or places this Lease or any amount payable by Tenant
hereunder with an attorney for the enforcement of any of Landlord's rights
hereunder, then Tenant agrees to pay to Landlord the reasonable attorney's fees
and other costs and expenses incurred by Landlord in connection therewith.

         30. JOINT AND SEVERAL LIABILITY. If there are two or more parties
comprising Tenant, the obligations imposed upon Tenant pursuant to this Lease
shall be joint and several. If there is a guarantor of Tenant's obligations
under this Lease, the obligations of Tenant shall be joint and several
obligations of Tenant and such guarantor, and Landlord need not first proceed
against Tenant hereunder before proceeding against such guarantor; nor shall any
such guarantor be released from its guarantee for any reason whatsoever,
including, without limitation, any amendment of this Lease, any forbearance by
Landlord or waiver of any of Landlord's rights, the failure to give Tenant or
such guarantor any notices, or the release of any party liable for the payment
of Tenant's obligations hereunder.

         31. CONSTRUCTIVE EVICTION. Tenant shall not be entitled to claim a
constructive eviction from the Premises unless Tenant shall have first notified
Landlord in writing of the condition or conditions giving rise thereto, and, if
the complaints be justified, unless Landlord shall have failed to remedy such
conditions within a reasonable time after receipt of said notice.

         32. BUILDING NAME. Landlord reserves the right at any time to change
the name by which the Building is designated, and Landlord shall have no
obligation or liability whatsoever for costs or expenses incurred by Tenant as a
result of such name change of the Building.

         33. SUBORDINATION. This Lease and all rights of Tenant hereunder are
subject and subordinate to any deeds of trust, mortgages or other instruments of
security which do now or



                                       17
<PAGE>   18

may hereafter cover the Building and the Land or any interest of Landlord
therein, and to any and all advances made on the security thereof, and to any
and all increases, renewals, modifications, consolidations, replacements and
extensions of any of such deeds of trust, mortgages or instruments of security.
This provision is hereby declared by Landlord and Tenant to be self-operative
and no further instrument shall be required to effect such subordination of this
Lease. Tenant shall, however, upon demand at any time or times execute,
acknowledge and deliver to Landlord any and all instruments and certificates
that, in the judgment of Landlord, may be necessary or proper to confirm or
evidence such subordination, and Tenant hereby irrevocably appoints Landlord as
Tenant's agent and attorney-in-fact for the purpose of executing, acknowledging
and delivering any such instruments and certificates. However, notwithstanding
the generality of the foregoing provisions of this Paragraph 33, Tenant agrees
that any such mortgagee shall have the right at any time to subordinate any such
deeds of trust, mortgages or other instruments of security to this Lease on such
terms and subject to such conditions as such mortgagee may deem appropriate in
its discretion. Tenant further covenants and agrees upon demand by Landlord's
mortgagee at any time, before or after the institution of any proceedings for
the foreclosure of any such deeds of trust, mortgages or other instruments of
security, or sale of the Building pursuant to any such deeds of trust, mortgages
or other instruments of security or voluntary sale, to attorn to such purchaser
upon any such sale and to recognize and attorn to such purchaser as Landlord
under this Lease. The agreement of Tenant to attorn upon demand of Landlord's
mortgagee contained in the immediately preceding sentence shall survive any such
foreclosure sale or trustee's sale. Tenant hereby agrees to execute, acknowledge
and deliver to Landlord's mortgagee any and all instruments and certificates
that in the judgment of Landlord's mortgagee may be necessary or proper to
confirm or evidence such attornment, and Tenant hereby irrevocably appoints
Landlord's mortgagee as Tenant's agent and attorney-in-fact for the purpose of
executing, acknowledging and delivering any such instruments and certificates.

         34. LEASE CERTIFICATES; FINANCIAL STATEMENTS. Tenant agrees to furnish
from time to time, within ten (10) days after requested by Landlord, a
certificate signed by Tenant and addressed to Landlord -- or at Landlord's
direction to any potential successor to Landlord or any existing or potential
holder of a deed of trust or mortgage covering the Land and Building or any
interest of Landlord therein -- to the effect that this Lease is then presently
in full force and effect and specifying any modifications; that the term of this
Lease has commenced and the full rental is then accruing hereunder; that Tenant
has accepted possession of the Premises and that any improvements required by
the terms of this Lease to be made by Landlord have been completed to the
satisfaction of Tenant; that no rent under this Lease has been paid more than
thirty (30) days in advance of its due date; that the address for notices to be
sent to Tenant is as set forth in this Lease; that Tenant, as of the date of
such certificate, has no charge, lien or claim of offset under this Lease or
otherwise against rents or other charges due or to become due hereunder; and
that to the knowledge of Tenant, Landlord is not then in default under this
Lease. The certificate shall also contain an acknowledgment by Tenant of receipt
of notice of the assignment of this Lease to such holder and the agreement by
Tenant with such holder that from and after the date of such certificate, Tenant
will not pay any rent under this Lease more than 30 days in advance of its due
date, will not surrender or consent to the modification of any of the terms of
this Lease nor to the termination of this Lease by Landlord, and will not seek
to terminate this Lease by reason of any act or omission of Landlord until
Tenant shall have given written notice of such act or omission to the holder of
such deed of trust or mortgage (at such holder's last address furnished to
Tenant) and until a reasonable period of time shall have elapsed following the
giving of such notice, during which period such holder shall have the right, but
shall not be obligated, to remedy such act or omission; provided, however, that
if Tenant's certificate is executed before the assignment of Landlord's interest
in the Lease to such holder, then the agreement of Tenant described in this
sentence will be of no effect under such certificate unless Tenant is furnished
with a copy of the assignment to such holder within ninety (90) days after the
date of such certificate. Tenant shall also furnish to Landlord when requested
by Landlord, but no more often than one time per calendar year, a statement of
the financial condition of Tenant prepared by an independent Certified Public
Accountant and in form reasonably satisfactory to Landlord.

         35. LIMITATION OF LANDLORD LIABILITY. The liability of Landlord to
Tenant for any default by Landlord under the terms of this Lease shall be
limited to the interest of Landlord in the Building and the Land, and Landlord
shall not be personally liable for any deficiency. This clause shall not be
deemed to limit or deny any remedies which Tenant may have in the event of



                                       18
<PAGE>   19

default by Landlord hereunder which do not involve the personal liability of
Landlord. Notwithstanding anything to the contrary contained in this Lease, in
the event Landlord sells, assigns, transfers or conveys its interest in the
Land, Landlord shall have no liability for any acts or omissions that occur
after the date of said sale, assignment, transfer or conveyance.

         36. CONSENTS. In all circumstances under this Lease where the prior
consent of one party (the "consenting party"), whether it be Landlord or Tenant,
is required before the other party (the "requesting party") is authorized to
take any particular type of action, such consent shall not be withheld in a
wholly unreasonable and arbitrary manner; however, the requesting party agrees
that its exclusive remedy if it believes that consent has been withheld
improperly (including, but not limited to, consent required from Landlord
pursuant to Paragraph 11 or Paragraph 21 of this Lease) shall be to institute
litigation either for a declaratory judgment or for a mandatory injunction
requiring that such consent be given (with the requesting party hereby waiving
any claim for damages, attorneys fees or any other remedy unless the consenting
party refuses to comply with a court order or judgment requiring it to grant its
consent).

         37. NOTICES. Any notice required or permitted to be given hereunder by
one party to the other shall be deemed to be given when deposited in the United
States mail, certified or registered mail, return receipt requested, with
sufficient postage prepaid, or hand delivered, addressed to the respective party
to whom notice is intended to be given at the address of such party set forth
below its name where it has executed this Lease. Either party hereto may at any
time by giving written notice to the other party in the aforesaid manner
designate any other address in substitution of the foregoing address to which
any such notice shall be given.

         38. BROKERAGE. Landlord and Tenant warrant to each other that they have
not had any dealings with any broker or agent in connection with the negotiation
or execution of this Lease except for the Leasing Agent, or Agents, if any,
listed in Paragraph 1(j) of this Lease; and each party agrees to indemnify the
other party and hold the other party harmless from and against any and all
costs, expenses or liability for commissions or other compensation or charges
claimed by any other broker or agent, through commitments of the indemnifying
party with respect to this Lease.

         39. FORCE MAJEURE. Whenever a period of time is herein prescribed for
action to be taken by Landlord or Tenant, the party taking the action shall not
be liable or responsible for, and there shall be excluded from the computation
for any such period of time, any reasonable delays due to strikes, riots, acts
of God, shortages of labor or materials, war, governmental laws, regulations or
restrictions or any other causes of any kind whatsoever which are beyond the
reasonable control of such party; provided, however, in no event shall the
foregoing apply to the financial obligations of either Landlord or Tenant to the
other under this Lease, including Tenant's obligation to pay Base Rentals and
all other amounts payable to Landlord hereunder.

         40. NO THIRD PARTY BENEFICIARY. This Lease is for the sole benefit of
Landlord, its successors and assigns, and Tenant, its permitted successors and
assigns, and it is not for the benefit of any third party.

         41. SEVERABILITY. If any clause or provision of this Lease is illegal,
invalid or unenforceable under present or future laws effective during the term
of this Lease, then and in that event, it is the intention of the parties hereto
that the remainder of this Lease shall not be affected thereby, and it is also
the intention of the parties to this Lease that in lieu of each clause or
provision that is illegal, invalid or unenforceable, there be added as a part of
this Lease a clause or provision as similar in terms to such illegal, invalid or
unenforceable clause or provision as may be possible and be legal, valid and
enforceable.

         42. BINDING EFFECT. The provisions of this Lease shall be binding upon
and inure to the benefit of Landlord and Tenant, respectively, and to their
respective heirs, personal representatives, successors and assigns, subject to
the provisions of Paragraph 21, Paragraph 25, Paragraph 35 and Paragraph 46
hereof.

         43. APPLICABLE LAW; CONSENT TO JURISDICTION. This Lease shall be
governed by and construed in accordance with the laws of the State of Texas and
the laws of the United States applicable to transactions in the State of Texas.
Tenant hereby irrevocably agrees that any legal action or proceeding against it
with respect to this Lease may be maintained in the courts of



                                       19
<PAGE>   20

county where rent is payable under this Lease, or at Landlord's option in the
U.S. District Court for the Northern District of Texas; and Tenant hereby
consents to the jurisdiction and venue of such courts.

         44. ENTIRE AGREEMENT; NO WARRANTIES. This Lease contains the entire
agreement between the parties hereto with respect to the subject matter hereof
and supersedes any and all prior and contemporaneous agreements, understandings,
promises, and representations made by either party to the other concerning the
subject matter hereof and the terms applicable hereto. It is expressly agreed by
Tenant, as a material consideration for the execution of this Lease, that there
have been no agreements pertaining to the Premises, the Building or this Lease
not incorporated in writing herein and that this Lease shall not be altered,
waived, amended or extended, except by a written agreement signed by the parties
hereto, unless otherwise expressly provided herein. Landlord's duties and
warranties are limited to those set forth in this Lease, and shall not include
any implied duties or warranties, all of which are hereby disclaimed by Landlord
and waived by Tenant. In particular, Landlord disclaims, and Tenant waives, any
warranty that the Premises are suitable or fit for any particular purpose or
use.

         45. NO IMPLIED REPRESENTATIONS. LANDLORD AND TENANT HEREBY ACKNOWLEDGE
THAT THEY ARE NOT RELYING UPON ANY BROCHURE, RENDERING, INFORMATION,
REPRESENTATION, PROMISE OR UNDERSTANDING OF THE OTHER, OR OF ANY LEASING AGENT,
EXCEPT AS MAY BE EXPRESSLY SET FORTH [place an "X" or other mark designating a
choice in the appropriate box]:


    [X]           IN THIS LEASE.


    [ ]           IN _______________________________AS WELL AS IN THIS
                  LEASE.

NOTE: IF NO "X" (OR OTHER MARK DESIGNATING A CHOICE) IS PLACED IN EITHER BOX IN
THIS PARAGRAPH 45, THEN THE FIRST BOX WILL BE DEEMED TO HAVE BEEN MARKED.

         46. EFFECTIVE DATE. The submission by Landlord of this instrument to
Tenant for examination, negotiation or signature does not constitute an option
for, or a representation by Landlord regarding, a prospective lease. This Lease
shall be effective if and when (and only if and when) it has been executed by
both Landlord and Tenant. When such condition has been satisfied, the effective
date of this Lease shall be the latest date accompanying a signature by Landlord
and Tenant below; and if either or both signatures fail to be accompanied by a
date, then the date of such signature(s) shall be established by the best
alternative evidence. If for any reason whatsoever this Lease has not been fully
executed within fifteen (15) business days after the signature of the first
party to sign, then this Lease shall be null and void and of no force or effect;
provided, however, that if more than 15 business days elapse between the dates
upon which Landlord and Tenant sign this Lease, but this Lease nevertheless is
in fact fully executed by both parties and following the execution of this Lease
by both parties and Tenant occupies the Premises, then the immediately preceding
provision of this sentence shall be inoperative and the remainder of this Lease
shall be in full force and effect.


                          [SIGNATURES ON THE NEXT PAGE]



                                       20
<PAGE>   21

                                      LANDLORD:


                                      CHARTER CROWN PLAZA PARTNERS, L.P.
                                      a Texas limited partnership

                                      By: Charter Crown Plaza Investments, Inc.,
                                          its General Partner


                                      By:
                                         ---------------------------------------
                                         Ray W. Washburne
                                         President

                                      Address: 2711 Cedar Springs Road
                                               Dallas, TX  75201

                                      Date of Signature:
                                                        ------------------------



                                      TENANT:


                                      MIGRATEC, INC.,
                                      a  Florida corporation


                                      By:
                                         ---------------------------------------
                                      Name:
                                           -------------------------------------
                                      Title:
                                            ------------------------------------

                                      Address (Before Commencement Date):

                                            ------------------------------------

                                            ------------------------------------

                                      Address (After Commencement Date):

                                            ------------------------------------

                                            ------------------------------------

                                      Date of Signature:
                                                        ------------------------



                                       21
<PAGE>   22

                          EXHIBIT A TO LEASE AGREEMENT

                         [legal description of the Land]


BEING LOT 2A, BLOCK A, LUNA 635 BUSINESS PARK ADDITION, an addition to the City
of Farmers Branch, Dallas County, Texas, according to the Revised Map thereof
recorded in Volume 81138, Page 2802, Map Records of Dallas County, Texas, and
being more particularly described by metes and bounds as follows:

BEGINNING at a 1/4" iron rod found for corner in the south right-of-way line of
Crown Drive (a 64ft, R.O.W.): said iron rod being the most northerly point of a
corner cut-off at the present intersection of the south line of Crown Drive with
the east R.O.W. line of Luna Road (a 105' R.O.W.);

THENCE EAST, 577.41 feet with the south ROW line of Crown Drive to a 1/4" iron
rod found for corner at the northwest corner of Lot 3, Block A of the LUNA 635
BUSINESS PARK ADDITION, an addition to the City of Farmers Branch, Dallas
County, Texas, as recorded in Volume 79042, Page 2188, of the Deed Records of
Dallas County, Texas;

THENCE South 36935 feet with the west line of Lot 3 and 4 of said addition to a
5/8" iron rod set for corner;

THENCE North 89 degrees 54 minutes 30 seconds West, 592.36 feet to a 3/8" iron
rod found for corner in the east line of Luna Road;

THENCE North 00 degrees 47 minutes 49 seconds East, 358.59 feet with the east
line of Luna Road to a 1/4" iron rod found for corner at a corner cut-off;

THENCE North 45 degrees 20 minutes 33 seconds East, 14.01 feet with the cut-off
line to the POINT OF BEGINNING and containing 217,514 square feet or 4.9934
acres of land, more or less.



                                       22
<PAGE>   23

                          EXHIBIT B TO LEASE AGREEMENT

                         [Floor Plan(s) of the Premises]



                                       23
<PAGE>   24

                          EXHIBIT C TO LEASE AGREEMENT

                               PARKING PRIVILEGES

1.       PARKING SPACES. At all times during the Lease Term, and conditioned
         upon the Lease being in full force and effect and there being no
         uncured default under this Lease as defined in Paragraph 26 of this
         Lease, Landlord hereby agrees to make available to Tenant one parking
         space for each 250 square feet of Rentable Space in the Premises. The
         location of such spaces shall be selected by Landlord in its sole
         discretion, and Landlord reserves the right to change the location of
         such spaces from time to time.

2.       PARKING RENTAL. The rent for all parking spaces which are allotted to
         Tenant pursuant to Paragraph 1 immediately above shall be the rate
         which is from time to time designated by Landlord as standard for the
         Building. On the execution date of the Lease, the rate is $0.00 for
         each parking space. After the initial term of the lease, Landlord shall
         provide Tenant at least thirty (30) days notice of any change in the
         parking rates, and Tenant shall pay the adjusted rent after the
         expiration of the 30-day notice period. All payments of rent for
         parking spaces shall be made (i) at the same time as each Base Rental
         is due under the Lease and (ii) to Landlord or to such persons as
         Landlord may direct from time to time.

3.       PARKING ALLOCATION DEVICES. Landlord reserves the right to institute,
         and from time to time change, a system for allocating parking spaces,
         e.g., magnetic parking cards, parking stickers and other devices or
         forms of identification. If Landlord issues magnetic parking cards,
         parking stickers or any other device or form of identification, they
         shall remain the property of Landlord and shall not be transferable.
         Tenant will be obligated to pay a replacement charge, equal to the
         amount posted from time to time by Landlord, for loss or other
         replacement of any magnetic parking card, parking sticker or other
         parking allocation device issued by Landlord.

4.       DAMAGE TO OR CONDEMNATION. If Landlord fails or is unable to provide
         any parking space to Tenant pursuant to Paragraph 1 above because of
         damage or condemnation, such failure or inability shall never be deemed
         to be a default by Landlord as to permit Tenant to terminate the Lease,
         either in whole or in part. Instead, Tenant's obligation to pay rent
         for any such parking space, which is not provided by Landlord shall be
         abated for so long as Tenant does not have the use of such parking
         space, and such abatement shall constitute full settlement of all
         claims that Tenant might otherwise have against Landlord by reason of
         such failure or inability to provide Tenant with such parking space.

5.       RULES AND REGULATIONS. A condition of any parking shall be compliance
         by the parker with garage or lot rules and regulations, including any
         sticker or other identification system which may be established by
         Landlord. The following rules and regulations are in effect until
         notice is given to Tenant of any change. Landlord reserves the right to
         modify and/or adopt such other reasonable and generally applicable
         rules and regulations for the applicable parking areas as it deems
         necessary for the operation of such areas.

         (a)      Cars must be parked entirely within the painted stall lines.

         (b)      All directional signs and arrows must be observed.

         (c)      The speed limit shall be five (5) miles per hour.

         (d)      Parking is prohibited in areas not striped for parking,
                  aisles, areas where "no parking" signs are posted, in cross
                  hatched areas and in such other areas as may be designated by
                  Landlord or Landlord's agent(s) including, but not limited to,
                  areas designated as "Visitor Parking" or reserved spaces not
                  rented under this Agreement.

         (e)      Every parker is required to park and lock his or her own car.
                  All responsibility for damage to cars or persons or loss of
                  personal possessions is assumed by the parker.



                                       24
<PAGE>   25

         (f)      Spaces which are designated for small, intermediate or
                  full-sized cars shall be so used. No intermediate or full-size
                  cars shall be parked in parking spaces limited to compact
                  cars.

6.       SPECIAL PROVISIONS REGARDING OVER-PARKING. Landlord agrees to use its
         good faith efforts to monitor the parking usage of tenants in the
         Building and attempt to restrict tenants against permitting their
         owners, officers, employees, agents and invitees to utilize more
         parking spaces than they are allotted pursuant to their respective
         leases. Tenant agrees to cooperate with Landlord's efforts in this
         regard. In addition, and without limiting the generality of the
         immediately preceding sentence, Tenant further agrees that if and to
         the extent requested in writing by Landlord because of Landlord's
         concern that Tenant's owners, officers, employees, agents and/or
         invitees are utilizing more parking spaces than Tenant has been
         allotted under this Exhibit C, then at Landlord's option any one or
         more of the following shall apply (i.e., the following are cumulative
         and not mutually exclusive):

         (a)      Tenant shall deliver written notices to all employees and
                  other persons who might be utilizing parking spaces, advising
                  them of the parking limits under this Exhibit C.

         (b)      Tenant shall furnish to Landlord a complete list of license
                  numbers of all automobiles operated by Tenant and its owners,
                  officers, employees, agents and invitees who might be
                  utilizing parking spaces.

         (c)      If any automobile or other vehicle owned by Tenant or any of
                  its employees, agents or other invitees is utilizing a parking
                  space in excess of those allotted to Tenant under this Exhibit
                  C, Tenant shall pay to Landlord as additional rent upon demand
                  an amount equal to the daily rate or charge for such parking
                  as established by Landlord from time to time for each day, or
                  part thereof, that such automobile or other vehicle is so
                  parked.

         (d)      If any overparking by Tenant, its employees, agents and other
                  invitees, persists after written notice thereof from Landlord
                  to Tenant, such continued overparking shall constitute a
                  failure of Tenant to comply with this Exhibit C; and such
                  written notice from Landlord shall constitute the "written
                  notice thereof" which is contemplated in item (ii) of Section
                  26(a) of this Lease, i.e., the overparking shall constitute an
                  event of default under this Lease if not cured within 30 days
                  after such written notice.



                                       25
<PAGE>   26

                          EXHIBIT D TO LEASE AGREEMENT

                        LEASEHOLD IMPROVEMENTS AGREEMENT


THIS LEASEHOLD IMPROVEMENTS AGREEMENT (this "AGREEMENT") is hereby incorporated
into the attached Lease Agreement (the "LEASE"), executed concurrently herewith
by and between the "LANDLORD" and the "TENANT" described in such Lease, and
constitutes the entire agreement of Landlord and Tenant with respect to the
construction and completion of the Premises described in the Lease. In the event
of a conflict between the provisions of this Agreement and other provisions of
the Lease, the provisions of this Agreement, as amended, will control. Terms
defined in the Lease, when used herein, shall have the same meanings as are
ascribed to them in the Lease.

         1. Premises Condition. Subject to the provisions of this Agreement,
Tenant has agreed to accept the Premises "as is," in their presently existing
condition. Tenant acknowledges having inspected the Premises.

         2. At such time that Landlord leases the Refusal Space to a third party
or Landlord deems necessary Landlord will construct a building standard demising
wall in the area shown on Exhibit B.



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<PAGE>   27

                          EXHIBIT E TO LEASE AGREEMENT

                         BUILDING RULES AND REGULATIONS

         1. Sidewalks, doorways, vestibules, corridors, stairways and other
similar areas shall not be obstructed by Tenant or used by Tenant for any
purpose other than ingress and egress to and from the Premises and for going
from or to another part of the Building.

         2. Plumbing fixtures and appliances shall be used only for the purposes
for which designed, and no sweepings, rubbish, rags or other unsuitable
materials shall be thrown or placed therein. Damage resulting to any such
fixtures or appliances or surrounding areas from misuse by Tenant shall be
repaired at the sole cost and expense of Tenant, and Landlord shall not in any
case be responsible therefor.

         3. No signs, advertisements or notices shall be painted or affixed on
or to any windows or doors or other parts of the Building except of such color,
size and style and in such places as shall be first approved in writing by
Landlord. No nails, hooks or screws shall be driven or inserted in any part of
the Building except by the Building maintenance personnel nor shall any part of
the Building be defaced by Tenant. No curtains or other window treatments will
be placed between the glass and the Building standard window treatments.

         4. Landlord will provide and maintain an alphabetical directory of each
Tenant's firm name on the first floor (main lobby) of the Building. No other
directory shall be permitted unless previously consented to by Landlord in
writing.

         5. Tenant shall not place any additional lock or locks on any doors in
or to the Premises without Landlord's prior written consent. A reasonable number
of keys to the locks on the doors which access the Premises from the Common
Areas shall be furnished by Landlord to Tenant, and Tenant shall not have any
duplicate keys made. Upon termination of the Lease, Tenant shall return all keys
to Landlord and shall provide to Landlord a means of opening all safes, cabinets
and vaults being left with the Premises.

         6. With respect to work being performed by Tenant in the Premises with
the approval of Landlord, Tenant will refer all contractors, contractor's
representatives and installation technicians rendering any service to them to
Landlord for Landlord's supervision, approval and control before the performance
of any contractual services. This provision shall apply to work performed in the
Building including, but not limited to, installation of telephones, telegraph
equipment, electrical devices and attachments, and any and all installation of
every nature affecting floors, walls, woodwork, trim, windows, ceilings,
equipment and any other physical portion of the Building. Tenant must have
Landlord's written approval prior to employing any contractor. Any and all such
contractors shall comply with these Rules and Regulations for such services
including, but not limited to, insurance requirements. All work in or on the
Building shall comply with any and all codes.

         7. Movement in or out of the Building of furniture or office equipment,
or dispatch or receipt by Tenant of any bulky materials, merchandise or
materials which require use of elevators or stairways, or movement through the
Building entrances or lobby shall be restricted to such hours as Landlord shall
designate. All such movement shall be under the supervision of Landlord and in
the manner agreed between Tenant and Landlord by prearrangement before
performance. Such prearrangement initiated by Tenant will include determination
by Landlord, and subject to its decision and control, as to the time, method and
routing of movement and as to limitations for safety or other concerns which may
prohibit any article, equipment or any other item from being brought into the
Building. Tenant is to assume all risk as to damage to articles moved and injury
to person or public engaged or not engaged in such movement, including
equipment, property and personnel of Landlord and other tenants if damaged or
injured as a result of acts in connection with carrying out this service for
Tenant from the time of entering the property to completion of work; and
Landlord shall not be liable for acts of any person engaged in, or any damage or
loss to any of said property or persons resulting from any act in connection
with such service performed for Tenant.



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<PAGE>   28

          8. Landlord shall have the power to prescribe the weight and position
of safes and other heavy equipment, which shall, in all cases, be positioned to
distribute the weight and stand on supporting devices approved by Landlord. All
damage done to the Building by taking in or putting out any property of Tenant,
or done by Tenant's property while in the Building, shall be repaired at the
expense of Tenant.

          9. Tenant, in its capacity as an employer, shall establish -- and
shall use reasonable measures to enforce -- a policy for its employees which
prohibits firearms (including, but not limited to, concealed handguns) in the
Building and the Premises.

         10. Tenant shall cooperate with Landlord's employees in keeping its
Premises neat and clean. Tenant shall not employ any person for the purpose of
such cleaning other than the Building's cleaning and maintenance personnel.
Landlord shall be in no way responsible to Tenant, its agents, employees or
invitees for any loss of property from the Premises or public areas or for any
damage to any property thereon from any cause whatsoever.

         11. To insure orderly operation of the Building, no ice, mineral or
other water, towels, newspapers, etc. shall be delivered to the Premises except
by persons appointed or approved by Landlord in writing.

         12. Corridor doors, when not in use, shall be kept closed.

         13. Should Tenant require telegraphic, telephonic, annunciator or other
communication service, Landlord will direct the electrician in writing where and
how wires are to be introduced and placed and none shall be introduced or placed
except as Landlord shall direct. Electric current shall not be used for power in
excess of standard office use or heating without Landlord's prior written
permission. Landlord shall have the sole discretion as to which communication
company or companies are permitted to enter the Building and service tenants in
the Building.

         14. Tenant shall not make or permit any improper odors or noises in the
Building or otherwise interfere in any way with other tenants or persons having
business with them.

         15. Nothing shall be swept or thrown into the corridors, halls,
elevator shafts or stairways. No animals shall be brought into or kept in, on or
about the Premises.

         16. No machinery other than standard office equipment shall be operated
by Tenant in its Premises without the prior written consent of Landlord, nor
shall Tenant use or keep in the Building any flammable or explosive fluid or
substance.

         17. No portion of the Premises shall at any time be used or occupied as
sleeping or lodging quarters.

         18. Landlord will not be responsible for money, jewelry or other
personal property lost or stolen in or from the Premises or public areas
regardless of whether such loss or theft occurs when the area is locked against
entry or not.

         19. Landlord reserves the right to rescind any of these rules and
regulations and to make such other and further rules and regulations as in its
judgment shall from time to time be advisable for the safety, protection, care
and cleanliness of the Building, the use and operation thereof, the preservation
of good order therein and the protection and comfort of the tenants and their
agents, employees and invitees, which rules and regulations, when made and
written notice thereof is given to Tenant, shall be binding upon Tenant in like
manner as if originally herein prescribed; provided, however, that no new rules
or regulations shall deprive Tenant of any rights expressly granted to Tenant
pursuant to this Lease.



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<PAGE>   29

                                                                   Rider No. 101


                            TENANT'S OPTION TO RENEW




         Tenant may, at its option, renew the term of this Lease for one (1)
additional term(s) of 60 months each, provided that this Lease must be in full
force and effect under the original term or any valid renewal thereof, and
Tenant shall not be in default in any of its obligations under this Lease at the
time of exercise of such option or at the time the renewal term would begin.
Each renewal shall be upon the same terms and conditions as provided elsewhere
in this Lease, except that (i) the original term of this Lease may not be
renewed more often than as set forth above, (ii) Landlord shall have no
obligation to install improvements in the Premises, and (iii) the annual Base
Rental for such renewal period(s), i.e., to be payable in equal monthly
installments in the same manner as during the primary Lease Term, shall be the
Prevailing Rental Rate (described below) . Each such option shall be exercised
by Tenant's giving notice to Landlord by certified mail, return receipt
requested, at least one year prior to the end of the then-existing term; and, if
not so exercised, such option shall automatically expire and terminate (i.e.,
time being of the essence).

         For purposes of determining the annual Base Rental for each renewal
period, the "PREVAILING BUILDING RENTAL RATE" shall mean the annual rental rate
then being charged by Landlord in the project for space comparable to the
Premises, taking into consideration use, location and floor level within the
Building, rental concessions then being granted by Landlord under similar
circumstances, the date the particular rate under consideration is to become
effective, and the term of the lease under consideration.



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<PAGE>   30

                                                                   Rider No. 102


            TENANT'S RIGHT OF FIRST REFUSAL TO LEASE ADDITIONAL SPACE



1. Provided that this Lease continues in full force and effect without any
uncured default by Tenant, Tenant shall have a right of first refusal to lease
any vacant space in the area(s) designated in Paragraph 2 below (with the
designated area(s) being hereinafter referred to as the "DESIGNATED AREA"),
which Landlord intends to market for lease to a party or parties other than the
current tenant(s) thereof. The right granted by this Rider, however, is subject
to the following terms and conditions:

         (a) If a proposed tenant, i.e., other than the current tenant in the
         space, gives Landlord an expression of interest in leasing then vacant
         space within the Designated Area (either as a separate leased premises
         or together with space outside the Designated Area), and if Landlord
         intends to enter into a lease with the proposed tenant for such space,
         Landlord shall deliver to Tenant a written notice which (i) specifies
         the portion or portions of the Designated Area and, if applicable, any
         other space in the Building which the proposed tenant wishes to lease
         and Landlord intends to allow to be leased along with the portion or
         portions of the Designated Area (all such space being referred to
         collectively as the "REFUSAL SPACE"), (ii) identifies the proposed
         tenant, (iii) summarizes what Landlord considers to be the most
         significant business terms of the proposed lease, and (iv) offers to
         lease the Refusal Space to Tenant on the same terms and conditions as
         Landlord intends to offer to the proposed tenant. Tenant shall then
         have a period of seven (7) business days from the delivery of such
         notice (the "DELIVERY DATE") to accept the lease offered by Landlord.
         If within the 7 business-day period Tenant does not give Landlord
         written notice of its acceptance of the lease offered by Landlord (time
         being of the essence), then Landlord shall be entitled to execute with
         the proposed tenant identified in Landlord's notice to Tenant (or with
         an "affiliated entity," i.e., an entity affiliated to such identified
         proposed tenant by common ownership), a lease of the Refusal Space for
         the same or better (for Landlord) terms as stated in the notice to
         Tenant. If within one hundred eighty (180) days after the Delivery Date
         Landlord does so execute a lease of the Refusal Space, this right of
         first refusal shall terminate (i.e., as to the entirety of the
         Designated Area) and this Rider shall have no further force or effect.
         If Landlord does not execute a lease of the Refusal Space with the
         proposed tenant or an affiliated entity within one hundred eighty (180)
         days after the Delivery Date, then Landlord shall again comply with the
         terms of this Rider in marketing the portion of the Refusal Space which
         is in the Designated Area.

         (b) Notwithstanding the fact that this Rider is a right of first
         refusal, Landlord and Tenant further agree that if the Refusal Notice
         for any Refusal Space is delivered by Landlord on or before October 31,
         2000, then the Refusal Space shall be leased under the same conditions
         as to rent, Landlord's obligation for a finish-out Allowance and lease
         term (i.e., 39 months) and other provisions as if included in the
         Premises on the Commencement Date of the Lease Term, with the following
         exceptions:

                  (1) The Commencement Date for the Refusal Space shall be as
                  designated by Landlord in the Refusal Notice.

2. For purposes of this Rider, the term "DESIGNATED AREA" shall be deemed to
mean:

         The remaining 3,835 rentable square feet on the first floor of 11494
Luna Road.



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<PAGE>   31

                                                                   Rider No. 103


                       PROJECT DESCRIPTION AND APPLICATION



         Landlord and Tenant acknowledge that the Building described in this
Lease is included within an office building project identified below (the
"PROJECT"), which contains more than one office building. Accordingly, the
parties agree that all references to the term "Building" in Paragraph 1(n) of
this Lease (entitled "Rentable Space") and Paragraph 4 of this Lease (entitled
"Adjustment of Base Rental") shall be changed to the term "Project"; moreover,
such change shall also be effected in other provisions of this Lease where in
Landlord's reasonable determination a "Project" reference is more appropriate
than a "Building" reference.




PROJECT DESCRIPTION:


Name of the Project:  Crown Plaza Business Park

Number of Office Buildings Within the Project:  3



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<PAGE>   32

                                                                   Rider No. 104


                         SPECIAL SIGN RIGHTS FOR TENANT


1. At all times during the Lease Term, and conditioned upon this Lease being in
full force and effect and there being no uncured event of default (as specified
in Paragraph 26 of the text of this Lease) under this Lease by Tenant, Tenant
shall have the following sign rights:

         (i)      For as long as MigraTEC, Inc. ("MIGRATEC") occupies at least
                  9,988 square feet of the Premises, MigraTEC may place its
                  building fascia sign on the top of the 2nd story of the west
                  side of the Building which face Luna Road. The exact location,
                  manner of installation, size, shape, specifications and design
                  of the fascia sign shall be subject to Landlord's approval
                  (not to be unreasonably withheld or delayed), as well as the
                  approvals (if any, and with Landlord making no representations
                  or warranties in this regard, except as expressly set out in
                  Paragraph 2 of this Rider) required by any city government or
                  other zoning or regulatory authority. Landlord hereby reserves
                  the right to place or to permit to be placed additional signs
                  on the Land and/or Building, i.e., the right granted in this
                  subsection is a non-exclusive right. The cost of Tenant's sign
                  shall be borne solely by Tenant; moreover, at the conclusion
                  of the Lease Term, if Landlord so requests, Tenant shall, at
                  its sole expense, promptly remove its fascia sign and restore
                  any damage caused to the Building by the fascia sign.

         (ii)     Notwithstanding anything to the contrary contained above in
                  this Paragraph 1, the parties agree as follows:

                  (A)      Tenant's sign rights in this Paragraph 1 are
                           contingent upon MigraTEC's leasing and being "in
                           possession" (as defined in subsection (B) immediately
                           below) of at least 9,988 square feet of Rentable
                           Space in the Building. Accordingly, if at any time
                           MigraTEC is not leasing and in possession of at least
                           9,988 square feet of Rentable Space in the Building,
                           and if Tenant fails to cure such failure within
                           thirty (30) days after Landlord's written notice to
                           Tenant, then for as long as MigraTEC is not "in
                           possession," Tenant shall not be entitled to the sign
                           rights specified in this Paragraph 1.

                  (B)      For purposes of subsection (A) immediately above,
                           MigraTEC shall not be entitled to include as space
                           which it is "in possession" (as that term is used in
                           subsection (A) above) any Rentable Space which it has
                           assigned or subleased to any party other than as
                           permitted in Paragraph 21 of this Lease; however,
                           MigraTEC shall be deemed to be "in possession" of
                           space which it has vacated but has not subleased or
                           assigned.



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