Document:

<PAGE>   1
                                                                 EXHIBIT 10.11

                                 STOCK PURCHASE AGREEMENT

     THIS STOCK PURCHASE AGREEMENT (the "Agreement") is made this day 20th May
1999 by and between LANDA MANAGEMENT SYSTEMS CORPORATION, a California
corporation (the "Company"), and Bryan H. Lang, ("Purchaser").

                                  WITNESSETH:

         WHEREAS, Purchaser holds a stock option dated October 20th, 1998 to
purchase shares of common stock of the Company (the "Option") pursuant to the
Company's 1998 Equity Incentive Plan (the "Plan") which Purchaser desires to
exercise; and

         WHEREAS, Purchaser wishes to take advantage of the early exercise
provision of the Option, and therefore to enter into this Agreement.

         NOW, THEREFORE, IT IS AGREED between the parties as follows:

         1. Purchaser hereby agrees to purchase from the Company, and the
Company hereby agrees to sell to Purchaser, an aggregate of one hundred ninety
five thousand (195,000) shares of the common stock (the "Stock") of the
Company, for a purchase price of 12/100 US dollars ($0.12) per share (total
purchase price: Twenty three thousand four hundred 00/100 US dollars
($23,400.00)), payable as follows:

<TABLE>

<S>                                                <C>
               Cash at Closing                       $      0.00

               Promissory Note in the form
               of Exhibit D (the "Note")             $ 23,400.00
                                                     -----------
               Total Purchase Price                  $ 23,400.00
                                                     ===========
</TABLE>

The closing hereunder shall occur at the offices of the Company on the date of
this Agreement or at such other time and place as the parties may mutually agree
upon in writing.

         At the closing, Purchaser shall deliver two (2) stock assignments in
the form of Exhibit B, duly endorsed (with date and number of shares left
blank), joint escrow instructions (the "Joint Escrow Instructions") in the form
of Exhibit C, duly executed by Purchaser, and the total purchase price
(including an executed Note in the form of Exhibit D if a portion of the total
purchase price is to be paid by promissory note and an executed pledge agreement
in the form of Exhibit E (the "Pledge Agreement") under which all shares of the
Stock acquired by Note shall be pledged as collateral security for the payment
of the indebtedness represented by the Note.

         At the closing or as soon thereafter as practicable, the Company shall
deliver to the Escrow Agent (as defined in paragraph 8 below) shares
certificates for all of the Stock that is to be subject to the Purchase Option
(as defined in paragraph 2 below), and shall deliver share certificates to
Purchaser for all of the Stock, if any, that is not to be subject to the
Purchase Option or the Pledge

                                       1
<PAGE>   2

Agreement. The certificates for all of the Stock that is subject to the Pledge
Agreement but not the Purchase Option shall be retained by the Company as
security pursuant to the Pledge Agreement.

         2. The Stock to be purchased by Purchaser pursuant to this Agreement
shall be subject to the following option ("Purchase Option"):

               (a) In the event that Purchaser's Continuous Service (as that
term is defined in the Plan) shall terminate for any reason (including
Purchaser's death), or no reason, with or without cause, the Purchase Option may
be exercised. The Company shall have the right at any time within ninety (90)
days after such termination of Continuous Service, or such longer period as may
determined by the Company if such later repurchase is deemed necessary by the
Company for treatment of its stock as Qualified Small Business Stock under
Section 1202 of the Internal Revenue Code of 1986, as amended, and regulations
promulgated thereunder, to exercise its option to repurchase from Purchaser or
his personal representative, as the case may be, at the price per share paid by
Purchaser pursuant to this Agreement ("Option Price"), up to but not exceeding
the number of unvested shares of the Stock set forth on Exhibit A hereto, which
is incorporated herein by this reference.

               (b) In addition, and without limiting the foregoing Purchase
Option, if at any time during the term of the Purchase Option there occurs a
transaction described in Section 11(b) or 11(c) of the Plan (e.g., a
dissolution, liquidation, asset sale, merger, consolidation or reverse merger of
the Company), then: (i) the Company shall exercise the Purchase Option to the
same extent that the unvested portion of the Option would have terminated
pursuant to Section 11(b) or 11(c) of the Plan if the Option had not been
exercised pursuant to this Agreement, (ii) the Purchase Option shall lapse to
the same extent that the unvested portion of the Option would have automatically
accelerated pursuant to Section 11(c) of the Plan if the Option had not been
exercised pursuant to this Agreement or (iii) the Purchase Option may be
assigned to any successor to the Company to the same extent that the unvested
portion of the Option would have been assumed or substituted by such successor
if the Option had not been exercised pursuant to this Agreement, in which case
the Purchase Option shall apply on the same basis as set forth above to the
Stock or to the consideration received for the Stock by the Purchaser in the
transaction (as the case may be) if Purchaser's Continuous Service with such
successor terminates for any reason. The continuing or surviving entity shall be
deemed to be the successor to the Company for purposes of this Agreement, and
references herein to the "Company" shall be deemed to refer to such successor.

               (c) The Company shall be entitled to pay for any of the Stock
purchased pursuant to its Purchase Option at the Company's option in cash, by
offset against any indebtedness owing to the Company by Purchaser including
without limitation any note given in payment for the Stock, or a combination of
both.

               (d) This Agreement is not an employment contract and nothing in
this Agreement shall be deemed to create in any way whatsoever any obligation on
the part of Purchaser to continue in the employ of the Company or any Affiliate
(as defined in the Plan) thereof, or of the Company or any Affiliate thereof to
continue Purchaser in its employ. In addition, nothing in this Agreement shall
obligate the Company or any Affiliate thereof, their

                                       2

<PAGE>   3

respective stockholders, boards of directors, officers or employees to continue
any relationship that you might have as a director or consultant for the Company
or any Affiliate thereof.

         3. The Purchase Option may be exercised by giving written notice of
exercise delivered or mailed as provided in paragraph 14. Upon providing of such
notice and payment or tender of the purchase price, the Company shall become the
legal and beneficial owner of the Stock being purchased and all rights and
interests therein or related thereto.

         4. If from time to time during the term of the Purchase Option there is
any stock dividend or liquidating dividend or distribution of cash and/or
property, stock split or other change in the character or amount of any of the
outstanding securities of the Company, then, in such event, any and all new,
substituted or additional securities or other property to which Purchaser is
entitled by reason of his ownership of Stock will be immediately subject to the
Purchase Option and be included in the word "Stock" for all purposes of the
Purchase Option with the same force and effect as the shares of Stock then
subject to the Purchase Option. While the total Option Price shall remain the
same after each such event, the Option Price per share of Stock upon exercise of
the Purchase Option shall be appropriately adjusted.

         5. All certificates representing any shares of Stock of the Company
subject to the provisions of this Agreement shall have endorsed thereon legends
in substantially the following form:

            (a) "The shares represented by this certificate are subject to an
option set forth in an agreement between the Company and the registered holder,
or registered holder's predecessor in interest, a copy of which is on file at
the principal office of this Company. Any transfer or attempted transfer of any
shares subject to such option is void without the prior express written consent
of the issuer of these shares."

            (b) "These securities have not been registered under the Securities
Act of 1933. They may not be sold, offered for sale, pledged or hypothecated in
the absence of an effective registration statement as to the securities under
said Act or an opinion of counsel satisfactory to the Company that such
registration is not required."

            (c) The shares represented by this certificate are subject to a
right of first refusal option in favor of the Company and/or its assignee(s) as
provided in the Bylaws of the Company."

            (d) Any legend required to be placed thereon by the California
Commissioner of Corporations.

         6. Purchaser acknowledges that he or she is aware that the Stock to be
issued to him or her by the Company pursuant to this Agreement has not been
registered under the Securities Act of 1933, as amended (the "Act"), on the
basis that no distribution or public offering of the Stock is to be effected,
and in this connection acknowledges that the Company is relying on the following
representations. In this connection, Purchaser warrants and represents to the
Company that he or she is acquiring the Stock for investment and not with a view
to or for sale in

                                       3

<PAGE>   4
 connection with any distribution of the Stock or with any present intention of
distributing or selling the Stock and he or she does not presently have reason
to anticipate any change in circumstances or any particular occasion or event
which would cause him or her to sell the Stock. Purchaser recognizes that the
Stock must be held indefinitely unless it is subsequently registered under the
Act or an exemption from such registration is available and, further, recognizes
that the Company is under no obligation to register the Stock or to comply with
any exemption from such registration.

         7. Purchaser is aware that the Stock may not be sold pursuant to Rule
144 adopted under the Act unless certain conditions are met and until Purchaser
has held the Stock for the applicable holding period set forth in Rule 144.
Among the conditions for use of Rule 144 is the availability of specified
current public information about the Company. Purchaser recognizes that the
Company presently has no plans to make such information available to the public.

         Whether or not the Purchase Option is exercised or has lapsed,
Purchaser further agrees not to make any disposition of any of the Stock in any
event unless and until:

            (a) There is then in effect a registration statement under the Act
covering such proposed disposition and such disposition is made in accordance
with such registration statement; or

            (b) (i) Purchaser shall have notified the Company of the proposed
disposition and shall have furnished the Company with a detailed statement of
the circumstances surrounding the proposed disposition, and (ii) Purchaser shall
have given the Company an opinion of counsel, which opinion and counsel shall be
satisfactory to the Company, to the effect that such disposition will not
require registration of the Stock under the Act.

         8. As security for his faithful performance of the terms of this
Agreement and to insure the availability for delivery of Purchaser's Stock upon
exercise of the Purchase Option herein provided for, Purchaser agrees, at the
closing hereunder (or as soon thereafter as practicable), to deliver (or have
the Company deliver on the Purchaser's behalf) to and deposit with the Secretary
of the Company ("Escrow Agent"), as Escrow Agent in this transaction, two (2)
stock assignments duly endorsed (with date and number of shares left blank) in
the form attached hereto as Exhibit B, together with a certificate or
certificates evidencing all of the Stock subject to the Purchase Option; said
documents are to be held by the Escrow Agent and delivered by said Escrow Agent
pursuant to the Joint Escrow Instructions of the Company and Purchaser set forth
in Exhibit C attached hereto and incorporated herein by this reference, which
instructions shall also be delivered to the Escrow Agent at the closing
hereunder (or as soon thereafter as practicable).

         9. Purchaser shall not sell or transfer any of the Stock subject to the
Purchase Option or any interest therein so long as such Stock is subject to the
Purchase Option. In addition, the Purchaser agrees that the Company (or a
representative of the underwriters) may, in connection with the first
underwritten registration of the offering of any securities of the Company under
the Act, require that Purchaser not sell, dispose of, transfer, make any short
sale of, grant any option for the purchase of, or enter into any hedging or
similar transaction with the same economic

                                       4

<PAGE>   5

effect as a sale, any of the Stock or other securities of the Company held by
you, for a period of time specified by the underwriter(s) (not to exceed one
hundred eighty (180) days) following the effective date of the registration
statement of the Company filed under the Act.

         10. The Company shall not be required (a) to transfer on its books any
shares of Stock of the Company which shall have been sold or transferred in
violation of any of the provisions set forth in this Agreement or (b) to treat
as owner of such shares or to accord the right to vote as such owner or to pay
dividends to any transferee to whom such shares shall have been so transferred.

         11. Subject to the provisions of paragraphs 9 and 10 above, Purchaser
(but not any unapproved transferee) shall, during the term of this Agreement,
exercise all rights and privileges of a stockholder of the Company with respect
to the Stock.

         12. The shares of Stock purchased under the terms of this Agreement are
subject to the right of first refusal provided for in the Bylaws of the Company.

         13. The parties agree to execute such further instruments and to take
such further action as reasonably may be necessary to carry out the intent of
this Agreement.

         14. Any notice required or permitted hereunder shall be given in
writing and shall be deemed effectively given upon personal delivery or upon
deposit in any United States Post Office Box, by registered or certified mail
with postage and fees prepaid, addressed to the other party hereto at his
address hereinafter shown below his signature or at such other address as such
party may designate by ten (10) days' advance written notice to the other party
hereto.

         15. This Agreement shall bind and inure to the benefit of the
successors and assigns of the Company and, subject to the restrictions on
transfer herein set forth, inure to the benefit of and be binding upon
Purchaser, his heirs, executors, administrators, successors, and assigns.
Without limiting the generality of the foregoing, the Purchase Option of the
Company hereunder shall be assignable by the Company at any time or from time to
time, in whole or in part.

                                       5

<PAGE>   6

         IN WITNESS WHEREOF, the parties hereto have executed this Stock
Purchase Agreement as of the day and year first set forth above.

                                           LANDA MANAGEMENT SYSTEMS CORPORATION

                                           By:  /s/ STEPHEN P. KAY
                                              ----------------------------------
                                           Its: COO/CFO
                                               ---------------------------------

                               Address:    1072 Marauder Street, Suite A
                                           Chico, CA 95973

                                           /s/ BRYAN H. LANG
                                           -------------------------------------
                                           BRYAN H. LANG
                               Address:

ATTACHMENTS:

Exhibit A                 Vesting Schedule
Exhibit B                 Assignment Separate from Certificate
Exhibit C                 Joint Escrow Instructions
Exhibit D                 Promissory Note
Exhibit E                 Pledge Agreement

                                       6

<PAGE>   7

                                    EXHIBIT A

                                VESTING SCHEDULE

<TABLE>
<CAPTION>
IF CONTINUOUS SERVICE                        NUMBER OF UNVESTED SHARES
TERMINATES:                                  SUBJECT TO PURCHASE OPTION:
<S>                                         <C>
Before 28th February 1999                         195,000.0 shares

After 28th February 1999
 but before 31st March 1999                       146,250.0 shares

After 31st March 1999
 but before 30th April 1999                       142,187.5 shares

After 30th April 1999
 but before 31st May 1999                         138,125.0 shares

After 31st May 1999
 but before 30th June 1999                        134,062.5 shares

After 30th June 1999
 but before 31st July 1999                        130,000.0 shares

After 31st July 1999
 but before 31st August 1999                      125,937.5 shares

After 31st August 1999
 but before 30th September 1999                   121,875.0 shares

After 30th September 1999
 but before 31st October 1999                     117,812.5 shares

After 31st October 1999
 but before 30th November 1999                    113,750.0 shares

After 30th November 1999
 but before 31st December 1999                    109,687.5 shares
</TABLE>

                                       1
<PAGE>   8
                             EXHIBIT A (CONTINUED)
                               VESTING SCHEDULE

<TABLE>
<CAPTION>
IF CONTINUOUS SERVICE                                  NUMBER OF UNVESTED SHARES
TERMINATES:                                            SUBJECT TO PURCHASE OPTION:

<S>                                                    <C>
After 31st December 1999
  but before 31st January 2000                               105,625.0 shares

After 31st January 2000
  but before 28th February 2000                              101,562.5 shares

After 28th February 2000
  but before 31st March 2000                                  97,500.0 shares

After 31st March 2000
  but before 30th April 2000                                  93,437.5 shares

After 30th April 2000
  but before 31st May 2000                                    89,375.0 shares

After 31st May 2000
  but before 30th June 2000                                   85,312.5 shares

After 30th June 2000
  but before 31st July 2000                                   81,250.0 shares

After 31st July 2000
  but before 31st August 2000                                 77,187.5 shares

After 31st August 2000
  but before 30th September 2000                              73,125.0 shares

After 30th September 2000
  but before 31st October 2000                                69,062.5 shares
</TABLE>

                                       2
<PAGE>   9
                             EXHIBIT A (CONTINUED)
                               VESTING SCHEDULE

<TABLE>
<CAPTION>
IF CONTINUOUS SERVICE                                  NUMBER OF UNVESTED SHARES
TERMINATES:                                            SUBJECT TO PURCHASE OPTION:

<S>                                                    <C>
After 31st October 2000
  but before 30th November 2000                              65,000.0 shares

After 30th November 2000
  but before 31st December 2000                              60,937.5 shares

After 31st December 2000
  but before 31st January 2001                               56,875.0 shares

After 31st January 2001
  but before 28th February 2001                              52,812.5 shares

After 28th February 2001
  but before 31st March 2001                                 48,750.0 shares

After 31st March 2001
  but before 30th April 2001                                 44,687.5 shares

After 30th April 2001
  but before 31st May 2001                                   40,625.0 shares

After 31st May 2001
  but before 30th June 2001                                  36,562.5 shares

After 30th June 2001
  but before 31st July 2001                                  32,500.0 shares

After 31st July 2001
  but before 31st August 2001                                28,437.5 shares
</TABLE>

                                       3
<PAGE>   10
                             EXHIBIT A (CONTINUED)
                               VESTING SCHEDULE

<TABLE>
<CAPTION>
IF CONTINUOUS SERVICE                                  NUMBER OF UNVESTED SHARES
TERMINATES:                                            SUBJECT TO PURCHASE OPTION:

<S>                                                    <C>
After 31st August 2001
  but before 30th September 2001                             24,375.0 shares

After 30th September 2001
  but before 31st October 2001                               20,312.5 shares

After 31st October 2001
  but before 30th November 2001                              16,250.0 shares

After 30th November 2001
  but before 31st December 2001                              12,187.5 shares

After 31st December 2001
  but before 31st January 2002                                8,125.0 shares

After 31st January 2002
  but before 28th February 2002                               4,062.5 shares

After 28th February 2002                                          0.0 shares
</TABLE>

                                       4
<PAGE>   11
                                   EXHIBIT B

                      ASSIGNMENT SEPARATE FROM CERTIFICATE

         FOR VALUE RECEIVED and pursuant to that certain Stock Purchase
Agreement dated as of 20th May 1999, (the "Agreement") Bryan H. Lang hereby
sells, assigns and transfers unto Landa Management Systems Corporation
_____________(___) shares of common stock of Landa Management Systems
Corporation, a California corporation, standing in the undersigned's name on the
books of said corporation represented by Certificate No. _____ herewith, and
does hereby irrevocably constitute and appoint _______________ attorney to
transfer the said stock on the books of the said corporation with full power of
substitution in the premises. This Assignment may be used only in accordance
with and subject to the terms and conditions of the Agreement, in connection
with the repurchase of shares of Common Stock issued to the undersigned pursuant
to the Agreement, and only to the extent that such shares remain subject to the
Company's Purchase Option under the Agreement.

Dated:
      ----------

                                        /s/ BRYAN H. LANG
                                        ---------------------------------
                                        [Signature]

                                        Bryan H. Lang
                                        ---------------------------------

[INSTRUCTION: Please do not fill in any blanks other than the signature line.
The purpose of this Assignment is to enable the Company to exercise its
repurchase option set forth in the Agreement without requiring additional
signatures on the part of Purchaser.]

<PAGE>   12
                                   EXHIBIT B

                      ASSIGNMENT SEPARATE FROM CERTIFICATE

         FOR VALUE RECEIVED and pursuant to that certain Stock Purchase
Agreement dated as of 20th May 1999, (the "Agreement") Bryan H. Lang hereby
sells, assigns and transfers unto Landa Management Systems Corporation
_____________(___) shares of common stock of Landa Management Systems
Corporation, a California corporation, standing in the undersigned's name on the
books of said corporation represented by Certificate No. _____ herewith, and
does hereby irrevocably constitute and appoint _______________ attorney to
transfer the said stock on the books of the said corporation with full power of
substitution in the premises. This Assignment may be used only in accordance
with and subject to the terms and conditions of the Agreement, in connection
with the repurchase of shares of Common Stock issued to the undersigned pursuant
to the Agreement, and only to the extent that such shares remain subject to the
Company's Purchase Option under the Agreement.

Dated:
      ----------

                                        /s/ BRYAN H. LANG
                                        ---------------------------------
                                        [Signature]

                                        Bryan H. Lang
                                        ---------------------------------

[INSTRUCTION: Please do not fill in any blanks other than the signature line.
The purpose of this Assignment is to enable the Company to exercise its
repurchase option set forth in the Agreement without requiring additional
signatures on the part of Purchaser.]

<PAGE>   13
                                   EXHIBIT C

                           JOINT ESCROW INSTRUCTIONS

Stephen P. Kay, Company Secretary
Landa Management Systems Corporation
1072 Marauder, Suite A
Chico, CA 95973

Dear Sir:

     As Escrow Agent for both Landa Management Systems Corporation, a California
corporation ("Company"), and the undersigned purchaser of stock of the Company
("Purchaser"), you are hereby authorized and directed to hold the documents
delivered to you pursuant to the terms of that certain Stock Purchase Agreement
("Agreement"), dated 20TH MAY 1999, to which a copy of these Joint Escrow
Instructions is attached as Exhibit C in accordance with the following
instructions:

     1.   In the event the Company or an assignee shall elect to exercise the
Purchase Option set forth in the Agreement, the Company or its assignee will
give to Purchaser and you a written notice specifying the number of shares of
stock to be purchased, the purchase price, and the time for a closing hereunder
at the principal office of the Company. Purchaser and the Company hereby
irrevocably authorize and direct you to close the transaction contemplated by
such notice in accordance with the terms of said notice.

     2.   At the closing you are directed (a) to date any stock assignments
necessary for the transfer in question, (b) to fill in the number of shares
being transferred, and (c) to deliver same, together with the certificate
evidencing the shares of stock to be transferred, to the Company against the
simultaneous delivery to you of the purchase price (which may include suitable
acknowledgment of cancellation of indebtedness) of the number of shares of stock
being purchased pursuant to the exercise of the Purchase Option.

     3.   Purchaser irrevocably authorizes the Company to deposit with you any
certificates evidencing shares of stock to be held by you hereunder and any
additions and substitutions to said shares as specified in the Agreement.
Purchaser does hereby irrevocably constitute and appoint you as his
attorney-in-fact and agent for the term of this escrow to execute with respect
to such securities and other property all documents of assignment and/or
transfer and all stock certificates necessary or appropriate to make all
securities negotiable and complete any transaction herein contemplated.

     4.   This escrow shall terminate upon expiration or exercise in full of the
Purchase Option, whichever occurs first.

                                       1.
<PAGE>   14
     5.   If at the time of termination of this escrow you should have in your
possession any documents, securities, or other property belonging to Purchaser,
you shall deliver all of same to Purchaser and shall be discharged of all
further obligations hereunder; provided, however, that if at the time of
termination of this escrow you are advised by the Company that the property
subject to this escrow is the subject of a pledge or other security agreement,
you shall deliver all such property to the pledgeholder or other person
designated by the Company.

     6.   Except as otherwise provided in these Joint Escrow Instructions, your
duties hereunder may be altered, amended, modified or revoked only by a writing
signed by all of the parties hereto.

     7.   You shall be obligated only for the performance of such duties as are
specifically set forth herein and may rely and shall be protected in relying or
refraining from acting on any instrument reasonably believed by you to be
genuine and to have been signed or presented by the proper party or parties or
their assignees. You shall not be personally liable for any act you may do or
omit to do hereunder as Escrow Agent or as attorney-in-fact for Purchaser while
acting in good faith and any act done or omitted by you pursuant to the advice
of your own attorneys shall be conclusive evidence of such good faith.

     8.   You are hereby expressly authorized to disregard any and all warnings
given by any of the parties hereto or by any other person or corporation,
excepting only orders or process of courts of law, and are hereby expressly
authorized to comply with and obey orders, judgments or decrees of any court.
In case you obey or comply with any such order, judgment or decree of any
court, you shall not be liable to any of the parties hereto or to any other
person, firm or corporation by reason of such compliance, notwithstanding any
such order, judgment or decree being subsequently reversed, modified, annulled,
set aside, vacated or found to have been entered without jurisdiction.

     9.   You shall not be liable in any respect on account of the identity,
authority or rights of the parties executing or delivering or purporting to
execute or deliver the Agreement or any documents or papers deposited or called
for hereunder.

     10.  You shall not be liable for the outlawing of any rights under any
statue of limitations with respect to these Joint Escrow Instructions or any
documents deposited with you.

     11.  Your responsibilities as Escrow Agent hereunder shall terminate if you
shall cease to be Secretary of the Company or if you shall resign by written
notice to each party. In the event of any such termination, the Company may
appoint any officer or assistant officer of the Company as successor Escrow
Agent and Purchaser hereby confirms the appointment of such successor or
successors as his attorney-in-fact and agent to the full extent of your
appointment.

     12.  If you reasonably require other or further instruments in connection
with these Joint Escrow Instructions or obligations in respect hereto, the
necessary parties hereto shall join in furnishing such instruments.

     13.  It is understood and agreed that should any dispute arise with
respect to the delivery and/or ownership or right of possession of the
securities, you are authorized and

                                       2.
<PAGE>   15
directed to retain in your possession without liability to anyone all or any
part of said securities until such dispute shall have been settled either by
mutual written agreement of the parties concerned or by a final order, decree
or judgment of a court of competent jurisdiction after the time for appeal has
expired and no appeal has been perfected, but you shall be under no duty
whatsoever to institute or defend any such proceedings.

     14.  Any notice required or permitted hereunder shall be given in writing
and shall be deemed effectively given upon personal delivery, including
delivery by express courier or five days after deposit in the United States
Post Office, by registered or certified mail with postage and fees prepaid,
addressed to each of the other parties hereunto entitled at the following
addresses, or at such other addresses as a party may designate by ten days'
advance written notice to each of the other parties hereto:

     COMPANY:       Stephen P. Kay, Company Secretary
                    Landa Management Systems Corporation
                    1072 Marauder, Suite A
                    Chico, CA 95973

     PURCHASER:     Bryan H. Lang

     ESCROW AGENT:  Stephen P. Kay, Company Secretary
                    Landa Management Systems Corporation
                    1072 Marauder, Suite A
                    Chico, CA 95973

     15.  By signing these Joint Escrow Instructions you become a party hereto
only for the purpose of said Joint Escrow Instructions; you do not become a
party to the Agreement.

     16.  You shall be entitled to employ such legal counsel and other experts
(including without limitation the firm of Cooley Godward LLP) as you may deem
necessary properly to advise you in connection with your obligations hereunder.
You may rely upon the advice of such counsel, and may pay such counsel
reasonable compensation therefor. The Corporation shall be responsible for all
fees generated by such legal counsel in connection with your obligations
hereunder.

     17.  This instrument shall be binding upon and inure to the benefit of the
parties hereto and their respective successors and permitted assigns. It is
understood and agreed that references to "you" or "your" herein refer to the
original Escrow Agent and to any and all successor Escrow Agents. It is
understood and agreed that the Corporation may at any time or from time to time
assign its rights under the Agreement and these Joint Escrow Instructions in
whole or in part.

     18.  This Agreement shall be governed by and interpreted and determined
in accordance with the laws of the State of California, as such laws are
applied by California courts to contracts made to be performed entirely in
California by residents of that state.

                                       3.

<PAGE>   16

                                        Very truly yours,

                                        LANDA MANAGEMENT SYSTEMS CORPORATION

                                        By: /s/ STEPHEN P. KAY
                                           ---------------------------------
                                           Chief Financial Officer

                                        PURCHASER:

                                        /s/ BRYAN H. LANG
                                        ------------------------------------

ESCROW AGENT:

/s/ STEPHEN P. KAY
---------------------------------
Stephen P. Kay, Company Secretary

                                       4.
<PAGE>   17

                                   EXHIBIT D

                         FULL RECOURSE PROMISSORY NOTE

$23,400.00                                                        20TH MAY 1999

         FOR VALUE RECEIVED, the undersigned hereby unconditionally promises to
pay to the order of Landa Management Systems Corporation, a California
corporation (the "Company"), at Chico, California, or at such other place as the
holder hereof may designate in writing, in lawful money of the United States of
America and in immediately available funds, the principal sum of Twenty three
thousand four hundred 00/100 Dollars ($23,400.00) together with interest accrued
from the date hereof on the unpaid principal at the rate of 6.00% per annum, or
the maximum rate permissible by law (which under the laws of the State of
California shall be deemed to be the laws relating to permissible rates of
interest on commercial loans), whichever is less, as follows:

                  PRINCIPAL REPAYMENT. The outstanding principal amount
         hereunder shall be DUE AND PAYABLE IN FULL ON MAY 19TH, 2006.

                  INTEREST PAYMENTS. Interest shall be ACCRUED ANNUALLY and
         shall be calculated on the basis of a 360-day year for the actual
         number of days elapsed;

provided, however, that in the event that the undersigned's employment by or
association with the Company is terminated for any reason prior to payment in
full of this Note, this Note shall be accelerated and all remaining unpaid
principal and interest shall become due and payable immediately after such
termination. Moreover, the Company may, in connection with the first
underwritten registration of the offering of any securities of the Company under
the Securities Act of 1933, as amended (the "Securities Act"), require that this
Note shall be accelerated and all remaining unpaid principal and interest shall
become due and payable within two hundred ten (210) days following the
effective date of the registration statement of the Company filed under the
Securities Act.

         If the undersigned fails to pay any of the principal and accrued
interest when due, the Company, at its sole option, shall have the right to
accelerate this Note, in which event the entire principal balance and all
accrued interest shall become immediately due and payable, and immediately
collectible by the Company pursuant to applicable law.

         This Note may be prepaid at any time without penalty. All money paid
toward the satisfaction of this Note shall be applied first to the payment of
interest as required hereunder and then to the retirement of the principal.

         This Note is a full recourse promissory note. The full amount of this
Note is secured by a pledge of shares of Common Stock of the Company, and is
subject to all of the terms and provisions of the Stock Purchase Agreement and
the Pledge Agreement, each of even date herewith between the undersigned and the
Company.

                                       1.

<PAGE>   18
     The undersigned hereby represents and agrees that the amounts due under
this Note are not consumer debt, and are not incurred primarily for personal,
family or household purposes, but are for business and commercial purposes only.

     The undersigned hereby waives presentment, protest and notice of protest,
demand for payment, notice of dishonor and all other notices or demands in
connection with the delivery, acceptance, performance, default or endorsement
of this Note.

     The holder hereof shall be entitled to recover, and the undersigned agrees
to pay when incurred, all costs and expenses of collection of this Note,
including without limitation, reasonable attorneys' fees.

     This Note shall be governed by, and construed, enforced and interpreted
in accordance with, the laws of the State of California, excluding conflict of
laws principles that would cause the application of laws of any other
jurisdiction.

                                   Signed /s/ BRYAN H. LANG
                                          ----------------------
                                          Bryan H. Lang

                                       2.
<PAGE>   19

                                   EXHIBIT E

                                PLEDGE AGREEMENT

         1. As collateral security for the payment of that certain $23,400.00
promissory note issued this date to Landa Management Systems Corporation
("Pledgee") by the undersigned (hereinafter called "indebtedness"), the
undersigned hereby assigns, transfers to and pledges with the Pledgee the
securities listed on Schedule 1 hereto which were this day delivered to be
deposited with Pledgee, together with any stock rights, rights to subscribe,
dividends paid in cash or other property in connection with the complete or
partial liquidation of Pledgee, stock dividends, dividends paid in stock, new
securities or other property except cash dividends other than liquidating
dividends to which the undersigned is or may hereafter become entitled to
receive on account of such property, and in the event that the undersigned
receives any such, the undersigned will immediately deliver it to Pledgee to be
held by Pledgee hereunder in the same manner as the property originally pledged
hereunder. All property assigned, transferred to and pledged with Pledgee under
this paragraph is hereinafter called "collateral."

         At any time, without notice, and at the expense of the undersigned,
Pledgee in its name or in the name of its nominee or of the undersigned may, but
shall not be obligated to: (a) collect by legal proceedings or otherwise all
dividends (except cash dividends other than liquidating dividends), interest,
principal payments and other sums now or hereafter payable upon or on account of
said collateral; (b) enter into any extension, reorganization, deposit, merger,
or consolidation agreement, or any agreement in any way relating to or affecting
the collateral, and in connection therewith may deposit or surrender control of
such collateral thereunder, accept other property in exchange for such
collateral and do and perform such acts and things as it may deem proper, and
any money or property received in exchange for such collateral shall be applied
to the indebtedness or thereafter held by it pursuant to the provisions hereof;
(c) insure, process and preserve the collateral; (d) cause the collateral to be
transferred to its name or to the name of its nominee; (e) exercise as to such
collateral all the rights, powers, and remedies of an owner, except that so long
as the indebtedness is not in default the undersigned shall retain all voting
rights as to the collateral.

         The undersigned agrees to pay prior to delinquency all taxes, charges,
liens and assessments against the collateral, and upon the failure of the
undersigned to do so Pledgee at its option may pay any of them and shall be the
sole judge of the legality or validity thereof and the amount necessary to
discharge the same.

         All advances, charges, costs and expenses, including reasonable
attorneys' fees, incurred or paid by Pledgee in exercising any right, power or
remedy conferred by this agreement, or in the enforcement thereof, shall become
a part of the indebtedness secured hereunder and shall be paid to Pledgee by the
undersigned immediately and without demand.

         At the option of Pledgee and without necessity of demand or notice, all
or any part of the indebtedness of the undersigned shall immediately become due
and payable irrespective of any agreed maturity, upon the happening of any of
the following events: (a) failure to keep or perform any of the terms or
provisions of this agreement; (b) default in the payment of principal or
interest when due; (c) the levy of any attachment, execution or other process
against the

                                       1.

<PAGE>   20

collateral; or (d) the insolvency, commission of an act of bankruptcy, general
assignment for the benefit of creditors, filing of any petition in bankruptcy or
for relief under the provisions of Title 11, United States Code, Bankruptcy, of,
by, or against the undersigned.

         In the event of the nonpayment of any indebtedness when due, whether by
acceleration or otherwise, or upon the happening of any of the events specified
in the last preceding paragraph, Pledgee may then, or at any time thereafter, at
its election, apply, set off, collect or sell in one or more sales, or take such
steps as may be necessary to liquidate and reduce to cash in the hands of
Pledgee in whole or in part, with or without any previous demands or demand of
performance or notice or advertisement, the whole or any part of the collateral
in such order as Pledgee may elect, and any such sale may be made either at
public or private sale at its place of business or elsewhere, or at any broker's
board or securities exchange, either for cash or upon credit or for future
delivery; provided, however, that if such disposition is at private sale, then
the purchase price of the collateral shall be equal to the public market price
then in effect, or, if at the time of sale no public market for the collateral
exists, then, in recognition of the fact that the sale of the collateral would
have to be registered under the Securities Act of 1933 and that the expenses of
such registration are commercially unreasonable for the type and amount of
collateral pledged hereunder, Pledgee and the undersigned hereby agree that such
private sale shall be at a purchase price mutually agreed to by Pledgee and the
undersigned or, if the parties cannot agree upon a purchase price, then at a
purchase price established by a majority of three independent appraisers
knowledgeable of the value of such collateral, one named by the undersigned
within 10 days after written request by the Pledgee to do so, one named by
Pledgee within such 10 day period, and the third named by the two appraisers so
selected, with the appraisal to be rendered by such body within 30 days of the
appointment of the third appraiser. The cost of such appraisal, including all
appraiser's fees, shall be charged against the proceeds of sale as an expense of
such sale. Pledgee may be the purchaser of any or all collateral so sold and
hold the same thereafter in its own right free from any claim of the
undersigned or right of redemption. Demands of performance, notices of sale,
advertisements and presence of property at sale are hereby waived, and Pledgee
is hereby authorized to sell hereunder any evidence of debt pledged to it. Any
sale hereunder may be conducted by any officer or agent of Pledgee.

         The proceeds of the sale of any of the collateral and all sums received
or collected by Pledgee from or on account of such collateral shall be applied
by Pledgee to the payment of expenses incurred or paid by Pledgee in connection
with any sale, transfer or delivery of the collateral, to the payment of any
other costs, charges, attorneys' fees or expenses mentioned herein, and to the
payment of the indebtedness or any part hereof, all in such order and manner as
Pledgee in its discretion may determine. Pledgee shall pay any balance to the
undersigned.

         Pledgee shall be under no duty or obligation whatsoever to make or give
any presentments, demands for performance, notices of non-performance, protests,
notices of protest or notices of dishonor in connection with any obligations or
evidences of indebtedness held by Pledgee as collateral, or in connection with
any obligations or evidences of indebtedness which constitute in whole or in
part the indebtedness secured hereunder.

         Pledgee may at any time deliver the collateral or any part thereof to
the undersigned and the receipt of the undersigned shall be a complete and full
acquittance for the collateral so delivered, and Pledgee shall thereafter be
discharged from any liability or responsibility therefor.

                                       2.

<PAGE>   21

         Upon the transfer of all or any part of the indebtedness Pledgee may
transfer all or any part of the collateral and shall be fully discharged
thereafter from all liability and responsibility with respect to such collateral
so transferred, and the transferee shall be vested with all the rights and
powers of Pledgee hereunder with respect to such collateral so transferred; but
with respect to any collateral not so transferred Pledgee shall retain all
rights and powers hereby given.

         Until all indebtedness shall have been paid in full the power of sale
and all other rights, powers and remedies granted to Pledgee hereunder shall
continue to exist and may be exercised by Pledgee at any time and from time to
time irrespective of the fact that the indebtedness or any part thereof may have
become barred by any statute of limitations, or that the personal liability of
the undersigned may have ceased.

         Pledgee agrees that so long as the indebtedness is not in default
shares of Landa Management Systems Corporation common stock held hereunder as
collateral for the indebtedness shall be released from pledge as the
indebtedness is paid. Such releases shall be at the rate of one share for each
$0.12 of principal amount of indebtedness paid. Release from pledge, however,
shall not result in release from the provisions of those certain Joint Escrow
Instructions, if any, of even date herewith among the parties to this Pledge
Agreement and the Escrow Agent named therein or from the Repurchase Option of
Landa Management Systems Corporation, set forth in the Stock Purchase Agreement
dated 20th May 1999, if any, between the parties to this Pledge Agreement.

         The rights, powers and remedies given to Pledgee by this agreement
shall be in addition to all rights, powers and remedies given to Pledgee by
virtue of any statute or rule of law. Pledgee may exercise its Pledgee's lien or
right of setoff with respect to the indebtedness in the same manner as if the
indebtedness were unsecured. Any forbearance or failure or delay by Pledgee in
exercising any right, power or remedy hereunder shall not be deemed to be a
waiver of such right, power or remedy, and any single or partial exercise of any
right, power or remedy hereunder shall not preclude the further exercise
thereof; and every right, power and remedy of Pledgee shall continue in full
force and effect until such right, power or remedy is specifically waived by an
instrument in writing executed by Pledgee.

          Dated: 20th May 1999

                                   /s/ BRYAN H. LANG
                                   --------------------------------------------
                                   Bryan H. Lang

ATTACHMENT: Schedule 1

                                       3.

<PAGE>   22

                                   SCHEDULE 1
                                       TO
                                PLEDGE AGREEMENT

    195,000 shares of Common Stock in Landa Management Systems Corporation.<PAGE>   1
                                                                  EXHIBIT 10.12

                      LANDA MANAGEMENT SYSTEMS CORPORATION

                                VOTING AGREEMENT

     THIS VOTING AGREEMENT (the "Agreement") is made and entered into this 27th
day of February, 1998, by and among LANDA MANAGEMENT SYSTEMS CORPORATION, a
California corporation (the "Company"), those certain holders of the Company's
Common Stock and options to purchase Common Stock listed on Exhibit A hereto
(the "Key Shareholders") and the persons and entries listed on Exhibit B hereto
(the "Investors").

                                  WITNESSETH:

     WHEREAS, the Key Shareholders are the beneficial owners of an aggregate
of seven hundred fifty-eight thousand four hundred seventy-seven and
eighty-three one hundredths (758,477.83) shares of Common Stock and/or options
to purchase three hundred sixty-eight thousand eight hundred forty-eight
(368,848) shares of Common Stock and/or warrants to purchase three hundred fifty
thousand (350,000) shares of Common Stock of the Company; and

     WHEREAS, the Company proposes to sell shares of its Series D Preferred
Stock, (the "Series D Preferred Stock"), to the Investors pursuant to the
Series D Preferred Stock Purchase Agreement (the "Purchase Agreement") of even
date herewith (the "Financing");

     WHEREAS, in connection with the consummation of the Financing, the
Company, the Key Shareholders and the Investors have agreed to provide for the
future voting of their shares of the Company's capital stock as set forth below;

     NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

                                   ARTICLE 1

                                     VOTING

     1.1 COMMON SHARES; INVESTOR SHARES.

          1.1.1 The Key Shareholders each agree to hold all shares of voting
capital stock of the Company registered in their respective names or
beneficially owned by them as of the date hereof, and any and all other
securities of the Company legally or beneficially acquired by each of the Key
Shareholders after the date hereof (including but not limited to all shares of
Common Stock issued upon exercise of options and/or warrants to purchase Common
Stock; hereinafter collectively referred to as the "Common Shares"), subject to,
and to vote the Common Shares in accordance with, the provisions of this
Agreement.

          1.1.2 The Investors each agree to hold all shares of voting capital
stock of the Company now owned or hereinafter acquired by them (including but
not limited to all shares of Common Stock issued upon conversion of the
Company's Series D Preferred Stock) registered in their respective

                                       1.
<PAGE>   2
names or beneficially owned by them as of the date hereof and any and all other
securities of the Company legally or beneficially acquired by each of the
Investors after the date hereof) (hereinafter collectively referred to as the
"Investor Shares") subject to, and to vote the Investor Shares in accordance
with, the provisions of this Agreement.

     1.2  VOTING.

          (a)  At each election of directors in which the holders of Common
Stock and holders of Preferred Stock, voting together as a single class, are
entitled to elect directors of the Company, the Key Shareholders and Investors
shall consult each other and shall vote their respective shares of the Company's
voting stock so that at least such directors will be nominees that are mutually
acceptable to a majority in interest of the holders of Series D Preferred Stock.
It is anticipated that one of the directors to be elected pursuant to this
section will be Bryan Lang for so long as he remains an employee of the Company.

          (b)  Each Key Shareholder and each Investor agrees to vote its voting
stock in accordance with the voting of holders of a majority in interest of the
Series D Preferred Stock with respect to (i) the approval of any proposed
amendment to the Amended and Restated Articles of Incorporation of the Company
(the "Restated Articles"), (ii) the approval of any proposed amendment to the
Amended and Restated Bylaws of the Company, and (iii) any proposed Acquisition
or Asset Transfer (as each such term is defined in the Restated Articles).

     1.3  LEGEND.

          1.3.1     Concurrently with the execution of this Agreement, there
shall be imprinted or otherwise placed, on certificates representing the Common
Shares and the Investor Shares, and such legend shall be imprinted on each
Common Share issued upon exercise by a Key Shareholder of an option to purchase
Common Stock, the following restrictive legend (the "Legend"):

          "THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT
          TO THE TERMS AND CONDITIONS OF A VOTING AGREEMENT WHICH
          PLACES CERTAIN RESTRICTIONS ON THE VOTING OF THE SHARES
          REPRESENTED HEREBY. ANY PERSON ACCEPTING ANY INTEREST IN
          SUCH SHARES SHALL BE DEEMED TO AGREE TO AND SHALL BECOME
          BOUND BY ALL THE PROVISIONS OF SUCH AGREEMENT. A COPY OF
          SUCH VOTING AGREEMENT WILL BE FURNISHED TO THE RECORD HOLDER
          OF THIS CERTIFICATE WITHOUT CHARGE UPON WRITTEN REQUEST
          TO THE COMPANY AT ITS PRINCIPAL PLACE OF BUSINESS."

          1.3.2     The Company agrees that, during the term of this Agreement,
it will not remove, and will not permit to be removed (upon registration of
transfer, reissuance of otherwise), the Legend from any such certificate and
will place or cause to be placed the Legend on any new certificate issued to
represent Common Shares or Investor Shares theretofore represented by a
certificate carrying the Legend.

     1.4  SUCCESSORS. The provisions of this Agreement shall be binding upon
the successors in interest to any of the Common Shares or Investor Shares. The
Company shall not permit the transfer of

                                       2.
<PAGE>   3
any of the Common Shares or Investor Shares on its books or issue a new
certificate representing any of the Common Shares or Investor Shares unless and
until the person to whom such security is to be transferred shall have executed
a written Agreement, substantially in the form of this Agreement, pursuant to
which such person becomes a party to this Agreement and agrees to be bound by
all the provisions hereof as if such person were a Key Shareholder or Investor,
as applicable. Notwithstanding the foregoing, upon any transfer effected
pursuant to Section 2.3 of the Purchase Agreement, such transferee shall be
deemed to be an Investor hereunder and the shares of voting capital stock of the
Company then transferred to it and/or thereafter acquired by it shall be deemed
"Investor Shares."

     1.5  OTHER RIGHTS. Except as provided by this Agreement, each key
Shareholder and Investor shall exercise the full rights of a shareholder with
respect to the Common Shares and the Investor Shares, respectively.

                                   ARTICLE 2

                                  TERMINATION

     2.1  This Agreement shall continue in full force and effect from the date
hereof through the earliest of the following dates, on which it shall terminate
in its entirety:

          2.1.1 the date of the closing of a firmly underwritten public offering
of the Company's Common Stock pursuant to a registration statement filed with,
and declared effective under the Securities Act of 1933, as amended; or

          2.1.2 at such time as the Investors hold less than One Million
(1,000,000) shares of Series D Preferred Stock (as adjusted for stock splits
and the like); or

          2.1.3 ten (10) years from the date of this Agreement; or

          2.1.4 the date as of which the parties hereto terminate this
Agreement by written consent of a majority in interest of the Investors and a
majority in interest of the Key Shareholders.

                                   ARTICLE 3

                                 MISCELLANEOUS

     3.1  OWNERSHIP. Each Key Shareholder represents and warrants to the
Investors that (a) he now owns the Common Shares and/or Options and/or Warrants
to purchase Common Stock of the Company set forth opposite such person's name on
Exhibit A hereto, free and clear of liens or encumbrances, and has not, prior to
or on the date of this Agreement, executed or delivered any proxy or entered
into any other voting agreement or similar arrangement other than on which has
expired or terminated prior to the date hereof, and (b) such Key Shareholder has
full power and capacity to execute, deliver and perform this Agreement, which
has been duly executed and delivered by, and evidences the valid and binding
obligation of, such Key Shareholder enforceable in accordance with its terms.

     3.2  FURTHER ACTION. If and when the Common Shares are sold, each Key
Shareholder (or the personal representative of any Key Shareholder) shall do all
things and execute and deliver all documents and make all transfers, and cause
any transferee of the Common Shares to do all things and

                                       3.
<PAGE>   4
execute and deliver all documents, as may be necessary to consummate such sale
consistent with this Agreement.

     3.3  SPECIFIC PERFORMANCE. The parties hereto hereby declare that it is
impossible to measure in money the damages which will accrue to a party hereto
or to their heirs, personal representatives, or assigns by reason of a failure
to perform any of the obligations under this Agreement and agree that the terms
of this Agreement shall be specifically enforceable. If any party hereto or his
heirs, personal representatives, or assigns institutes any action of proceeding
to specifically enforce the provisions hereof, any person against whom such
action or proceeding is brought hereby waives the claim or defense therein that
such party or such personal representative has an adequate remedy at law, and
such person shall not offer in any such action or proceeding the claim or
defense that such remedy at law exists.

     3.4  GOVERNING LAW. This Agreement, and the rights of the parties hereto,
shall be governed by and construed in accordance with the laws of the State of
California as such laws apply to agreements among California residents made and
to be performed entirely within the State of California.

     3.5  AMENDMENT. This Agreement may be amended only by an instrument in
writing signed by the Company, a majority in interest of the Investors and a
majority in interest of the Key Shareholders.

     3.6  SEVERABILITY. If any provision of this Agreement is held to be invalid
or unenforceable, the validity and enforceability of the remaining provisions of
this Agreement shall not be affected thereby.

     3.7  SUCCESSORS. This Agreement shall inure to the benefit of and be
binding upon the parties hereto and their respective heirs, successors, assigns,
administrators, executors and other legal representatives.

     3.8  ADDITIONAL SHARES. In the event that subsequent to the date of this
Agreement any shares or other securities (other than any shares or securities of
another corporation issued to the Company's shareholders pursuant to a plan of
merger) are issued on, or in exchange for, any of the Common Shares or Investor
Shares by reason of any stock dividend, stock split, consolidation of shares,
reclassification or consolidation involving the Company, such shares or
securities shall be deemed to be Common Shares or Investor Shares, as the case
may be, for purposes of this Agreement.

     3.9  COUNTERPARTS. This Agreement may be executed in one or more
counterparts, each of which will be deemed an original but all of which together
shall constitute one and the same agreement.

     3.10 WAIVER. No waivers of any breach of this Agreement extended by any
party hereto to any other party shall be construed as a waiver of any rights or
remedies of any other party hereto or with respect to any subsequent breach.

     3.11 ATTORNEY'S FEES. In the event that any suit or action is instituted to
enforce any provision in this Agreement, the prevailing party shall be entitled
to all costs and expenses of maintaining such suit or action, including
reasonable attorneys' fees.

                                       4.
<PAGE>   5

     3.12 ENTIRE AGREEMENT. This Agreement and the Exhibits hereto, along with
the Purchase Agreement and each of the Exhibits thereto, constitute the full and
entire understanding and agreement between the parties with regard to the
subjects hereof and thereof and no party shall be liable or bound to any other
in any manner by any representations, warranties, covenants and agreements
except as specifically set forth herein and therein.

                     [THIS SPACE INTENTIONALLY LEFT BLANK]

                                       5.
<PAGE>   6
     IN WITNESS WHEREOF, the parties hereto have executed this VOTING AGREEMENT
as of the date first above written.

COMPANY:                                INVESTORS:

LANDA MANAGEMENT SYSTEMS CORPORATION    BEDROCK CAPITAL PARTNERS, L.L.P.

By:                                     By:
   ---------------------------------       ------------------------------------
     President                               General Partner

KEY SHAREHOLDERS:                       BEDROCK CAPITAL SIDE-BY-SIDE, L.P.

                                        By:
------------------------------------       ------------------------------------
BRYAN LANG                                   General Partner

------------------------------------    GREYLOCK IX LIMITED PARTNERSHIP
STEPHEN KAY                             By: Greylock IX GP Limited Partnership
                                        Its General Partner

                                        By:
------------------------------------       ------------------------------------
SHAREHOLDER                                  General Partner

                                        SEQUOIA CAPITAL VII,
                                        A CALIFORNIA LIMITED PARTNERSHIP
                                        By:  SC  VII-A  Management, LLC A
California
                                        Limited Liability Company,
                                        Its General Partner

                                        By:
                                           ------------------------------------
                                             Managing Member

                                        SEQUOIA TECHNOLOGY PARTNERS VII
                                        A CALIFORNIA LIMITED PARTNERSHIP
                                        By:  SC  VII-A  Management, LLC A
California
                                        Limited Liability Company,
                                        Its General Partner

                                        By:
                                           ------------------------------------
                                             Managing Member

                       SIGNATURE PAGE TO VOTING AGREEMENT
<PAGE>   7
                                        SQP 1997

                                        BY: SC VII-A MANAGEMENT, LLC A
                                        CALIFORNIA LIMITED LIABILITY COMPANY,
                                        ITS GENERAL PARTNER

                                        By:
                                           ---------------------------
                                             Managing Member

                                        SEQUOIA 1997 LLC

                                        BY: SC VII-A MANAGEMENT, LLC A
                                        CALIFORNIA LIMITED LIABILITY COMPANY,
                                        IT'S GENERAL PARTNER

                                        By:
                                           ---------------------------
                                             Managing Member

                                        SEQUOIA INTERNATIONAL PARTNERS

                                        BY: SC VII-A MANAGEMENT, LLC A
                                        CALIFORNIA LIMITED LIABILITY COMPANY,
                                        IT'S GENERAL PARTNER

                                        By:
                                           ---------------------------
                                             Managing Member

                                        ------------------------------
                                        GENE CATTARINA

                                        ------------------------------
                                        JOHN KARLEN

                       SIGNATURE PAGE TO VOTING AGREEMENT

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