<PAGE>

                                                                     Exhibit 4.1




THIS SENIOR NOTE WAS ISSUED IN A TRANSACTION THAT WAS NOT REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY
NOT BE OFFERED OR SOLD EXCEPT IN A TRANSACTION REGISTERED UNDER SUCH ACT AND
APPLICABLE STATE SECURITIES LAWS OR UNLESS AN EXEMPTION FROM SUCH REGISTRATION
IS AVAILABLE.

THIS SENIOR NOTE MAY NOT BE SOLD, ASSIGNED, PLEDGED, ENCUMBERED, DISPOSED OF OR
OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE WITH THE PROVISIONS OF SECTION 10
HEREOF.

NO TRANSFER OF THIS SENIOR NOTE WILL BE MADE ON THE BOOKS OF THE COMPANY UNLESS,
IF THE COMPANY SO REQUESTS, IT IS ACCOMPANIED BY AN OPINION OF LEGAL COUNSEL
EXPERIENCED IN SECURITIES ACT MATTERS, IN FORM AND SUBSTANCE REASONABLY
SATISFACTORY TO THE COMPANY, AND BY SUCH OTHER EVIDENCE AS THE COMPANY MAY
REASONABLY REQUIRE THAT AN EXEMPTION FROM REGISTRATION IS AVAILABLE UNDER THE
SECURITIES ACT AND ANY APPLICABLE STATE SECURITIES OR BLUE SKY LAW.

                        WIND RIVER INVESTMENT CORPORATION
                                 5% SENIOR NOTE
                              DUE SEPTEMBER 5, 2015

$[____]                                                       New York, New York

                                             Originally issued September 5, 2003

                            Reissued, as amended and restated, November __, 2003

            FOR VALUE RECEIVED, the undersigned, WIND RIVER INVESTMENT
CORPORATION, a Delaware corporation (the "Company"), hereby promises to pay to
the order of [_____] (together with their successors and assigns, the "Holder"),
the principal sum of [_____] ($[_____]) U.S. Dollars, as the same may be (1)
adjusted pursuant to Section 2 hereof or (2) increased by the amount of any
Additional Principal Amount (as defined in Section 3(a) hereof) (such principal
sum as so adjusted, together with any Additional Principal Amount, being
referred to herein as the "Principal Amount"), together with interest from
September 5, 2003 on the unpaid Principal Amount at 5% per annum (computed, for
actual days elapsed, as if each full calendar year consisted of 365 days). The
Principal Amount of this Senior Note is (1) payable in accordance with the
provisions of Sections 3(b) and 3(c) hereof, and (2) payable in full on the
earlier to occur of (a) a Change of Control (as defined in Section 1(a) hereof)
and (b) September 5, 2015 (such date, the "Maturity Date"). Payments of
principal and interest in cash are to be made by wire transfer to such bank
account of the Holder as the Holder may from time to time designate, in lawful
money of the United States of America. The Company shall pay accrued interest as
provided in Section 3 hereof. As used herein, the term "Senior Note" includes
this Senior Note and any Senior Note issued in exchange herefor or in
replacement hereof. This Senior Note is one of several senior notes issued by
the Company on or about September 5, 2003 and amended and restated on November
__, 2003 on substantially the terms set forth herein, which notes in the
aggregate are for an initial principal amount equal to $72,848,000 (this Senior
Note, together with all other such senior notes, together with any senior notes
issued in exchange herefor or in replacement hereof or exchange therefor or in
replacement thereof are collectively referred to as the "Related Senior Notes").
<PAGE>
            Section 1. Definitions.

            (a) The following terms, as used herein, have the following
meanings:

            "Additional Principal Amount" has the meaning given in Section 3(a)
hereof.

            "Affiliate" means, with respect to any person, any other person or
entity directly or indirectly controlling, controlled by or under common control
with, such person.

            "Cayman Parent" means United National Group, Ltd., an exempted
company formed with limited liability under the laws of the Cayman Islands.

            "Cayman Parent Board" means the Board of Directors of Cayman Parent.

            "Cayman Purchaser" means U.N. Holdings (Cayman), Ltd, an exempted
company formed with limited liability under the laws of the Cayman Islands.

            "Change of Control" means (i) the occurrence of any event or
condition, including, without limitation, the consummation of any merger,
consolidation or sale or purchase of securities, following which FPC and
Affiliates of FPC, together with investment funds managed or controlled by FPC
or by Affiliates of FPC cease (A) to have a majority of the outstanding voting
power of Cayman Parent, or (B) to own 25% of the outstanding common shares of
Cayman Parent on an as-converted, fully-diluted basis, or (ii) the sale of all
or substantially all of the assets of the Company and its subsidiaries, taken as
a whole, or Cayman Parent and its subsidiaries, taken as a whole, to any person
other than FPC or an Affiliate of FPC, or an investment fund managed or
controlled by FPC or any Affiliate of FPC.

            "Company" has the meaning given in the preamble hereof.

            "Company Board" means the Board of Directors of the Company.

            "Events of Default" has the meaning given in Section 4 hereof.

            "Excess Cash Flow" means, with respect to any fiscal year of Cayman
Parent, an amount equal to the consolidated net income of Cayman Parent and its
subsidiaries, as set forth in Cayman Parent's audited consolidated statement of
income for such fiscal year prepared in accordance with United States generally
accepted accounting principles, consistently applied, less such amount that the
Cayman Parent Board may in good faith reasonably determine is required to be
retained by Cayman Parent (i) to maintain an A.M. Best rating for each Material
Subsidiary of at least "A" (without any negative outlook or similar
qualification) following the payment required by Section 3(b); (ii) (A) to pay
dividends in cash in respect of the Series A Preferred Shares and (B) to pay
dividends in cash, direct or indirect, on any trust preferred or similar
securities that Cayman Parent or one of its subsidiaries may issue; provided, in
the case of this clause (ii), that the Company shall have made all payments of
interest required on this Senior Note in cash and that such dividends shall not
exceed $5 million per year; (iii) to maintain a level of statutory surplus
applicable to any Material Subsidiary in any jurisdiction in which it is
licensed so that the Material Subsidiary's Risk Based Capital is above the
Company Action Level as provided for in that jurisdiction following the payment
required by Section 3(b); or (iv) to

                                      -2-
<PAGE>
provide the Company with appropriate levels of working capital, taking into
account the levels and aging of the Company's reinsurance recoverables, in the
case of clauses (i), (iii) and (iv) assuming all cash and investment securities
held by Cayman Parent and its subsidiaries (other than the Material Subsidiaries
and, in the case of clause (iv), other than the Company and the Material
Subsidiaries) are contributed to the Company or the Material Subsidiaries as
needed for such purposes.

            "Excess Interest Payment Amount" means, as of any date, an amount
equal to the excess of (i) all interest paid in cash or Additional Principal
Amount prior to such date (but not including any interest amounts credited as
having been paid in accordance with the next to last sentence of Section 3(a)
hereof) together with all interest accrued but not yet paid as of such date over
(ii) the total amount of interest that would have been payable prior to such
date together with all interest that would have accrued as of such date had the
principal amount of this Senior Note been, as of September 5, 2003, the
principal amount of this Senior Note as subsequently adjusted in accordance with
Section 2 prior to such date.

            "FPC" means Fox, Paine & Co., LLC, a Delaware limited liability
company.

            "Guaranty Agreement" means the Amended and Restated Deed of
Guaranty, dated as of November __, 2003, by and among Cayman Parent and the
Trusts.

            "Holder" has the meaning given in the preamble hereof.

            "Interest Payment Date" has the meaning given in Section 3(a)
hereof.

            "Interest Underpayment Amount" means, as of any date, an amount
equal to the excess of (i) the total amount of interest that would have been
payable prior to such date together with all interest that would have accrued as
of such date had the principal amount of this Senior Note been, as of September
5, 2003, the principal amount of this Senior Note as subsequently adjusted in
accordance with Section 2 prior to such date over (ii) all interest paid in cash
or Additional Principal Amount prior to such date (but not including any
interest amounts credited as having been paid in accordance with the next to
last sentence of Section 3(a) hereof) together with all interest accrued but not
yet paid as of such date.

            "Investment Agreement" means the Amended and Restated Investment
Agreement, dated as of September 5, 2003, by and among Cayman Purchaser, Cayman
Parent, U.N. Holdings II, Inc., a Delaware corporation, U.N. Holdings LLC, a
Delaware limited liability company, U.S. Parent, the Company and the Trusts.

            "Mandatory Prepayment" has the meaning given in Section 3(b) hereof.

            "Mandatory Prepayment Date" has the meaning given in Section 3(b)
hereof.

            "Maturity Date" has the meaning given in the preamble hereof.

            "Material Subsidiary" means Diamond State Insurance Company, an
Indiana corporation, United National Casualty Insurance Company, an Indiana
corporation, United National

                                      -3-
<PAGE>
Insurance Company, a Pennsylvania corporation, and United National Specialty
Insurance Company, Inc., a Wisconsin corporation.

            "Principal Amount" has the meaning given in the preamble hereof.

            "Related Senior Notes" has the meaning given in the preamble hereof.

            "Restricted Payment" means (i) any dividend or other distribution,
direct or indirect, in respect of any class of capital stock or ownership
interest of the Company or any of its subsidiaries, now or hereafter
outstanding, except (A) a dividend payable solely in shares of common stock of
the Company pro rata to all holders, (B) a dividend payable by a subsidiary of
the Company to the Company or any other direct or indirect wholly-owned
subsidiary of the Company, or (C) a dividend payable by the Company to a direct
or indirect wholly-owned subsidiary of the Guarantor (as defined in the Guaranty
Agreement), and (ii) any redemption, retirement, purchase or other acquisition,
direct or indirect, of any shares of any class of capital stock or ownership
interest of the Company or any of its subsidiaries, now or hereafter
outstanding, or of any warrants, rights or options to acquire any such shares of
capital stock or other interests; provided, however, that any dividend or other
distribution in respect of, or payment made in redemption or other repurchase
of, any preferred stock or similar ownership interest of the Company issued
subject to Section 6.3 of the Shareholders Agreement shall not be a Restricted
Payment.

            "Securities Act" means the Securities Act of 1933, as amended.

            "Senior Notes" has the meaning given in the preamble hereof.

            "Series A Preferred Shares" means the Series A Preferred Shares, par
value $0.0001, of Cayman Parent.

            "Shareholders Agreement" means the Shareholders Agreement, dated as
of September 5, 2003, by and among Cayman Purchaser, Cayman Parent and the
Trusts.

            "Trusts" means those trusts set forth on Schedule A to the
Investment Agreement.

            "U.S. Parent" means U.N. Holdings, Inc., a Delaware corporation.

            (b) As used in this Senior Note, the expressions "pay in full,"
"paid in full" or "payment in full" mean, with respect to any indebtedness, the
final and indefeasible payment in full in cash of all such indebtedness in
accordance with its terms.

            Section 2. Adjustment of Principal Amount. The Principal Amount of
this Senior Note shall be subject to adjustment as contemplated by Sections 6.08
and 11.02(b) of the Investment Agreement. The Company, for its own benefit and
for the benefit of any Indemnified Person (as such term is defined in the
Investment Agreement) shall be entitled to reduce the Principal Amount by any
amounts that may become due and payable to any Indemnified Person pursuant to
the Investment Agreement in accordance with Section 11.02(b) of the Investment
Agreement and that are not first credited against interest payable pursuant to
the last sentence of

                                       -4-
<PAGE>
Section 3(a) hereof.

            Section 3. Repayments and Payments of Principal and Interest on this
Senior Note.

            (a) Interest. Except as provided in this Section 3(a), interest on
the unpaid balance of the Principal Amount will accrue at 5% per annum. Subject
to this Section 3(a), interest is payable in cash, in arrears, on October 1 of
each year, or, if such date is not a business day, on the immediately following
business day, on any Mandatory Prepayment Date and on the Maturity Date (each,
an "Interest Payment Date"). Notwithstanding anything herein to the contrary,
all interest due on any Interest Payment Date (other than the Maturity Date)
may, at the option of the Company, in lieu of being paid in cash, be added to
the outstanding principal amount of this Senior Note (such additional principal
amount from time to time being the "Additional Principal Amount") and, in such
event, the Principal Amount shall be deemed to be increased by the amount of
each Additional Principal Amount. Any Additional Principal Amount shall accrue
interest from the Interest Payment Date on which such Additional Principal
Amount was added. In the event that the principal amount of this Senior Note
shall be adjusted as contemplated by Section 2 hereof, (i) an amount of interest
due on any Interest Payment Date or Interest Payment Dates following such
adjustment not in excess of the Excess Interest Payment Amount may, at the
option of the Company, be credited against such interest and such interest shall
be deemed to have been paid in the form of such credit, or (ii) an amount of
interest equal to the Interest Underpayment Amount shall be payable on the
Interest Payment Date following such adjustment. The Company, for its own
benefit and for the benefit of any Indemnified Person (as such term is defined
in the Investment Agreement) shall be entitled to credit against part or all
interest payable under this Section 3(a) any amounts that may become due and
payable to any Indemnified Person pursuant to the Investment Agreement in
accordance with Section 11.02(b) of the Investment Agreement.

            (b) Mandatory Prepayments. From and after September 5, 2005, on
October 1 of each such year (each, a "Mandatory Prepayment Date") the Company
shall pay in cash an amount of the Principal Amount, and without any penalty or
premium with respect to any Principal Amount so prepaid, equal to the Excess
Cash Flow for the fiscal year of Cayman Parent ended immediately preceding such
Mandatory Prepayment Date, together with interest on the Principal Amount so
prepaid accrued to the applicable Mandatory Prepayment Date (each, a "Mandatory
Prepayment"). Notwithstanding the foregoing, the Company shall not be required
to repay, on any Mandatory Prepayment Date, the portion of any such Mandatory
Prepayment that, in the reasonable good faith judgment of the Cayman Parent
Board, equals the amount by which any amount that is likely to be due from the
Holder under Section 11.02(a) of the Investment Agreement (determined on a pro
rata basis, assuming that each Holder of a Related Note is responsible for its
proportionate share of such amount) in connection with a specifically identified
Claim (as that term is defined in the Investment Agreement) exceeds the
Principal Amount that would be outstanding following such Mandatory Prepayment.
If the Cayman Parent Board elects to withhold all or any portion of any
Mandatory Prepayment pursuant to the preceding sentence, it shall provide the
Holder with written notice detailing the basis for such withholding.

            (c) Optional Prepayments. Subject to the provisions of Section 5,
the Company may, at its option, prepay at any time all or, from time to time,
part of the Principal

                                      -5-
<PAGE>
Amount, and without penalty or premium with respect to any Principal Amount so
prepaid, together with interest on the Principal Amount so prepaid accrued to
the date fixed for such prepayment.

            Section 4. Events of Default; Acceleration. If any of the following
events ("Events of Default") occurs:

                  (a) the Company defaults in the payment of interest on this
      Senior Note when the same becomes due and payable and the default
      continues for a period of thirty days following the date of such default,
      and the Holder delivers written notice of such default; or

                  (b) the Company defaults in the payment of any of the
      Principal Amount when the same becomes due and payable at maturity or
      otherwise and, in the case of any Mandatory Prepayment, such default
      continues for a period of thirty days following the date of such default
      and the Holder delivers written notice of such default; or

                  (c) there occurs an "Event of Default" (as such term is
      defined in any Related Senior Note) under any other Related Senior Note;
      or

                  (d) there occurs any default by Cayman Parent under the
      Guaranty Agreement and such default continues for a period of thirty days
      following the date of such default; or

                  (e) the Company materially breaches any covenant provided in
      this Senior Note; or

                  (f) Cayman Parent materially breaches any covenant provided
      for in the Guaranty Agreement; or

                  (g) The Company, Cayman Parent or any of their respective
      subsidiaries makes an assignment for the benefit of creditors, or admits
      in writing its inability to pay its debts as they become due, or files a
      voluntary petition in bankruptcy, or is adjudicated a bankrupt or
      insolvent, or files any petition or answer seeking for itself any
      reorganization, arrangement, composition, readjustment, liquidation,
      dissolution or similar relief under any present or future statute, law or
      regulation, or files any answer admitting or failing to deny the material
      allegations of a petition filed against the Company, Cayman Parent or any
      of their respective subsidiaries for any such relief, or seeks or consents
      to or acquiesces in the appointment of any trustee, receiver or liquidator
      of the Company, Cayman Parent or any of their respective subsidiaries or
      of all or any substantial part of the properties of the Company, Cayman
      Parent or any of their respective subsidiaries, or the Company, Cayman
      Parent or any of their respective subsidiaries or the directors or
      majority stockholders of the Company, Cayman Parent or any of their
      respective subsidiaries take any action looking to the dissolution or
      liquidation of the Company, Cayman Parent or any of their respective
      subsidiaries; or

                                      -6-
<PAGE>
                  (h) if, within 60 days after the commencement of any
      proceeding against the Company, Cayman Parent or any of their respective
      subsidiaries seeking any reorganization, arrangement, composition,
      readjustment, liquidation, dissolution or similar relief under any present
      or future statute, law or regulation, such proceeding has not been
      dismissed or if, within 60 days after the appointment, without the consent
      or acquiescence of the Company, Cayman Parent or any of their respective
      subsidiaries, of any trustee, receiver or liquidator of the Company,
      Cayman Parent or any of their respective subsidiaries or of all or any
      substantial part of the properties of the Company, Cayman Parent or any of
      their respective subsidiaries, such appointment has not been vacated;

then and, in any such event, the Holder at its option may, by written notice or
notices to the Company, declare this Senior Note to be due and payable,
whereupon the same shall forthwith mature and become due and payable together
with interest accrued thereon, without presentment, demand, protest or notice,
all of which are hereby waived; provided, however, that such acceleration is
automatic without the necessity of any such notice in the case of Events of
Default under clause (g) or (h) of this Section 4 with respect to the Company or
Cayman Parent.

            Section 5. Remedies on Default, etc. (a) If an Event of Default has
occurred and is continuing, the Holder may proceed to protect and enforce its
rights by a suit in equity, action at law or other appropriate proceeding. No
course of dealing and no delay on the part of the Holder in exercising any
right, power or remedy will operate as a waiver thereof or otherwise prejudice
the Holder's rights, powers or remedies. No right, power or remedy conferred
hereby is exclusive of any other right, power or remedy referred to herein or
now or hereafter available at law, in equity, by statute or otherwise. To the
extent permitted by applicable law, the Company hereby agrees to waive, and does
hereby absolutely and irrevocably waive and relinquish, the benefit and
advantage of any valuation, stay, appraisement, extension or redemption law now
existing or which may hereafter exist, which, but for this provision, might be
applicable to any sale made under the judgment, order or decree of any court, or
otherwise, based on this Senior Note or on any claim for any of the Principal
Amount of, or interest on, this Senior Note.

            (b) If there shall occur any Event of Default under this Senior
Note, the Company shall, unconditionally upon demand, pay or reimburse the
Holder for all documented out-of-pocket expenses (including, without limitation,
reasonable fees and disbursements of legal counsel, accountants, investigators
and other experts) incurred by the Holder in connection with the protection,
preservation, exercise or enforcement of any of the rights or remedies of the
Holder under this Senior Note.

            Section 6. Covenants of the Company. The Company covenants and
agrees that until it has paid to the Holder in full all amounts owing in respect
of this Senior Note:

            (a) No Restricted Payments. The Company shall not, and shall not
permit any of its subsidiaries to, directly or indirectly, declare, order, pay,
make or set apart any sum or property for any Restricted Payment, except that if
the Company shall have made all payments of interest required on the Senior
Notes in cash, each of the Company and its subsidiaries may make payments as
dividends in cash on any trust preferred or similar securities that it or any of

                                      -7-
<PAGE>
its subsidiaries may issue; provided, that such dividends, together with cash
dividends paid by Cayman Parent in respect of the Series A Preferred Shares,
shall not exceed $5 million per year.

            (b) Limitations on Affiliate Transactions. The Company shall not,
and shall not permit any of its subsidiaries to, directly or indirectly, engage
in any transactions with FPC or any of its Affiliates or any other Affiliate of
the Company, or make an assignment or other transfer of properties or assets to
FPC or any of its Affiliates or any other Affiliate of the Company except (i)
transactions that, in the good faith judgment of the Company Board, are no less
favorable to the Company or the applicable subsidiary as it would obtain in an
arms-length transaction with an unaffiliated third party or (ii) transactions
and transfers among the Company and its wholly-owned subsidiaries.

            (c) Provision of Information.

                  (1) The Company shall deliver to the Holder, as and when
available after the end of each of the first three quarters of each fiscal year,
quarterly financial reports of the Company in the form prepared for the Company
Board and, unless otherwise delivered to the Holder by Cayman Parent pursuant to
the Guaranty Agreement, quarterly financial reports of Cayman Parent in the form
prepared for the Cayman Parent Board. Notwithstanding anything to the contrary
contained in the immediately preceding sentence, the Company shall deliver such
quarterly financial reports to the Holder within forty five (45) days after the
end of each relevant fiscal quarter (or, if the Company is in good faith and
diligently seeking to prepare and deliver such financial information, at such
later date (not exceeding sixty (60) days after the end of such quarter) as
circumstances may require); and

                  (2) The Company shall deliver to the Holder, within one
hundred and fifty (150) days after the end of the Company's fiscal year, (A) the
audited annual financial statements of the Company (including the notes
thereto), including consolidated and consolidating balance sheets, income
statements and statements of cash flow, accompanied by the audit report thereon
of the Company's independent public accountants and (B) unless otherwise
delivered to the Holder by Cayman Parent pursuant to the Guaranty Agreement, the
audited annual financial statements of Cayman Parent (including the notes
thereto), including consolidated and consolidating balance sheets, income
statements and statements of cash flow, accompanied by the audit report thereon
of Cayman Parent's independent public accountants.

            (d) No Merger. The Company shall not consolidate or merge with or
into, or sell, assign, transfer or lease all or substantially all of the assets
of the Company and its subsidiaries taken as a whole to any person in any
transaction not constituting a Change of Control unless the person formed by or
surviving any such consolidation or merger (if other than the Company), or to
which such sale or conveyance is made, assumes, by written instrument in form
and substance reasonably satisfactory to the Holder, all the obligations of the
Company arising under this Note. Notwithstanding the foregoing, the Company
shall not consolidate or merge with or into, or sell, assign, transfer or lease
all or substantially all of the assets of the Company and its subsidiaries taken
as a whole to any person in any transaction not constituting a Change of Control
if a primary purpose of such transaction is to avoid any restriction on the
Company contained in this Section 6.

                                      -8-
<PAGE>
            Section 7. Notice of Certain Events. The Company shall provide the
Holder with written notice of any Event of Default promptly following (and not
later than five business days following) any senior officer of the Company
obtaining actual knowledge thereof.

            Section 8. Amendments and Waivers. Neither this Senior Note nor any
term hereof may be amended or waived orally or in writing, except that any term
of this Senior Note may be amended and the observance of any term of this Senior
Note may be waived (either generally or in a particular instance and either
retroactively or prospectively) with (but only with) the written consent of the
Company and the Holder.

            Section 9. Notices. Any notice or communication must be given in
writing or delivered in person or sent by documented overnight delivery service
addressed as follows:

            if to the Company:

            Wind River Investment Corporation
            c/o Fox Paine & Company, LLC
            950 Tower Lane
            Suite 1150
            Foster City, California  94404
            Attention:  Saul A. Fox

            with a copy to:

            Wachtell, Lipton, Rosen & Katz
            51 West 52nd Street
            New York, New York  10019
            Attention:  Elliott V. Stein
                        Mitchell S. Presser

            if to the Holder:

            c/o The AMC Group, L.P.
            555 Croton Road, Suite 300
            King of Prussia, Pennsylvania  19406
            Attention:  President

            with a copy to:
            Drinker Biddle & Reath LLP
            One Logan Square
            18th and Cherry Streets
            Philadelphia, Pennsylvania  19103
            Attention:  Robert C. Juelke

All such notices, requests and other communications shall be deemed received on
the date of receipt by the recipient if received prior to 5 p.m. in the place of
receipt and such day is a business

                                      -9-
<PAGE>
day in the place of receipt. Otherwise, any such notice, request or
communication shall be deemed not to have been received until the next
succeeding business day in the place of receipt.

            Section 10. Restrictions on Transfer.

            (a) Subject to the provisions of clause (b) below, the Holder may
not sell, transfer, assign, encumber or otherwise dispose of this Senior Note;
provided, however, that the Holder may transfer this Senior Note to any Trust,
any Affiliate of the Trusts or to the principal (i.e. corpus) beneficiaries of
any Trust. Notwithstanding the foregoing sentence but subject to the provisions
of Section 10(b) hereof, if an Event of Default described in Section 5 hereof
has occurred and is continuing, no consent of the Company shall be required to
sell, transfer, assign, encumber or otherwise dispose of this Senior Note.

            (b) In addition to the foregoing, because this Senior Note has not
been registered under the Securities Act or any applicable state securities or
blue sky laws, it may not be sold, transferred or otherwise disposed of without
such registration unless the sale, transfer or disposition can be effected
without such registration and in compliance with the Securities Act and such
laws. The Holder shall not sell, transfer or otherwise dispose of all or any
part of this Senior Note other than pursuant to an effective registration
statement under the Securities Act, without first notifying the Company prior to
such sale, transfer or disposition and, if requested by the Company, delivering
to the Company a written opinion of legal counsel experienced in Securities Act
matters, in form and substance reasonably satisfactory to the Company, and by
such other evidence as the Company may reasonably require, that an exemption
from registration is available under the Securities Act and any applicable state
securities or blue sky law.

            Section 11. General.

            (a) This Senior Note is governed by and shall be construed and
enforced in accordance with the laws of the State of Delaware for contracts made
and wholly performed within that state and shall be construed as if drafted
equally by the parties.

            (b) This Senior Note amends and restates and reflects the same
indebtedness as the original Senior Note issued by the Company on September 5,
2003 (the "Original Senior Note"), in order to reflect changes in the terms of
the Senior Note. This Senior Note does not represent a novation or termination
of the debt evidenced by the Original Senior Note.

                                      -10-
<PAGE>
            IN WITNESS WHEREOF, the Company has caused this Senior Note to be
executed and delivered on the date first written above.

                                       WIND RIVER INVESTMENT CORPORATION


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


                         [SIGNATURE PAGE TO SENIOR NOTE]