Document:

DATED: OCTOBER 27, 2005

      NEITHER THIS DEBENTURE NOR THE SECURITIES INTO WHICH THIS DEBENTURE IS
      CONVERTIBLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE
      COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN
      EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED
      (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD
      EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE
      SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A
      TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE
      SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS.

No. CCP-4 $1,658,160

                            NETFABRIC HOLDINGS, INC.

               AMENDED AND RESTATED SECURED CONVERTIBLE DEBENTURE

                              DUE OCTOBER 27, 2008

      This Amended and Restated Secured Convertible Debenture (the "Debenture")
is issued by NETFABRIC HOLDINGS, INC., a Delaware corporation (the "Obligor"),
to CORNELL CAPITAL PARTNERS, LP (the "Holder"), pursuant to that certain
Securities Purchase Agreement (the "Securities Purchase Agreement") of even date
herewith. The Company issued to the Holder (i) on July 1, 2005 a secured
debenture in the amount of Four Hundred Thousand Dollars ($400,000) (the "July
2005 Debenture"), (ii) on September 1, 2005, a secured debenture in the amount
of Fifty Thousand Dollars ($50,000) (the "September 2005 Debenture"), and (iii)
on October 6, 2005, a secured debenture in the amount of Five Hundred Fifty
Thousand Dollars ($550,000), of which $150,000 was funded on October 6, 2005 and
$400,000 was funded on October 13, 2005 (the "October 2005 Debenture")
(collectively referred to as the "Prior Debentures"). This Debenture is being
re-issued to consolidate the Prior Debentures plus accrued and unpaid interest
to the date hereof ($6,555,56 as and for interest on the July 2005 Debenture,
$388.89 as and for interest on the September 2005 Debenture and $1,215.27 as and
for interest on the October 2005 Debenture) and to reflect the additional
funding in the amount of Six Hundred Fifty Thousand Dollars ($650,000), for the
total principal of One Million Six Hundred Fifty Eight Thousand One Hundred
Sixty Dollars ($1,658,160).

      FOR VALUE RECEIVED, the Obligor hereby promises to pay to the Holder or
its successors and assigns the principal sum of One Million Six Hundred Fifty
Eight Thousand One Hundred Sixty Dollars ($1,658,160) together with accrued but
unpaid interest on or before October 27, 2008 (the "Maturity Date") in
accordance with the following terms:

      Interest. Interest shall accrue on the outstanding principal balance
hereof at an annual rate equal to five percent (5%). Interest shall be
calculated on the basis of a 360-day year and the actual number of days elapsed,
to the extent permitted by applicable law. Interest hereunder will be paid to

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the Holder or its assignee (as defined in Section 4) in whose name this
Debenture is registered on the records of the Obligor regarding registration and
transfers of Debentures (the "Debenture Register").

      Right of Redemption. The Obligor at its option shall have the right, with
three (3) business days advance written notice (the "Redemption Notice"), to
redeem a portion or all amounts outstanding under this Debenture prior to the
Maturity Date. The Obligor shall pay an amount equal to the principal amount
outstanding and accrued interest being redeemed, plus a redemption premium of
fifteen percent (15%) ("Redemption Premium") of the amount redeemed
(collectively referred to as the "Redemption Amount"). The Obligor shall deliver
to the Holder the Redemption Amount on the third (3rd) business day after the
Redemption Notice.

      Notwithstanding the foregoing in the event that the Obligor has elected to
redeem a portion of the outstanding principal amount and accrued interest under
this Debenture the Holder shall still be entitled to effectuate Conversions as
contemplated hereunder.

      Security Agreements. This Debenture is secured an Amended and Restated
Security Agreement between the Obligor and the Holder of even date herewith (the
"Security Agreement"), an Officer Pledge and Escrow Agreement ("Officer Pledge
Agreement") of even date herewith among the Obligor, the Holder, the Pledgor and
the Escrow Agent and Amended and Restated Subsidiary Security Agreements between
the Holder and NetFabric Corporation, and UCA Services, Inc., both wholly-owned
subsidiaries of the Obligor (collectively, the Subsidiary Security Agreements).

      Consent of Holder to Sell Capital Stock or Grant Security Interests. So
long as any of the principal amount or interest on this Debenture remains unpaid
and unconverted, the Obligor shall not, without the prior consent of the Holder,
(i) issue or sell any common stock or preferred stock with or without
consideration, (ii) issue or sell any preferred stock, warrant, option, right,
contract, call, or other security or instrument granting the holder thereof the
right to acquire common stock with or without consideration, (iii) enter into
any security instrument granting the holder a security interest in any of the
assets of the Obligor, or (iv) file any registration statements on Form S-8,
except to register up to 9,000,000 shares of Common Stock issued pursuant to the
Obligor's 2005 stock option plan. Notwithstanding the forgoing, the Obligor
shall be entitled to issue or sell up to $5,000,000 of shares of common stock or
preferred stock for a consideration per share of up to 20% below the closing bid
price of the Common Stock determined immediately prior to its issuance, without
first obtaining the prior written consent of the Holder provided that the
Company obtains lock up agreements from the purchasers in connection with such
an issuance for a period of at least one year from the date of issuance of such
stock.

      This Debenture is subject to the following additional provisions:

      Section 1. This Debenture is exchangeable for an equal aggregate principal
amount of Debentures of different authorized denominations, as requested by the
Holder surrendering the same. No service charge will be made for such
registration of transfer or exchange.

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      Section 2. Events of Default.

      (a) An "Event of Default", wherever used herein, means any one of the
following events (whatever the reason and whether it shall be voluntary or
involuntary or effected by operation of law or pursuant to any judgment, decree
or order of any court, or any order, rule or regulation of any administrative or
governmental body):

            (i) Any default in the payment of the principal of, interest on or
other charges in respect of this Debenture, free of any claim of subordination,
as and when the same shall become due and payable (whether on a Conversion Date
or the Maturity Date or by acceleration or otherwise) which is not cured within
five (5) days of written notice of such default;

            (ii) The Obligor shall fail to observe or perform any other
covenant, agreement or warranty contained in, or otherwise commit any breach or
default of any provision of this Debenture (except as may be covered by Section
2(a)(i) hereof) or any Transaction Document (as defined in Section 4) which is
not cured within fifteen (15) days of written notice of such default;

            (iii) The Obligor or any subsidiary of the Obligor shall commence,
or there shall be commenced against the Obligor or any subsidiary of the Obligor
under any applicable bankruptcy or insolvency laws as now or hereafter in effect
or any successor thereto, or the Obligor or any subsidiary of the Obligor
commences any other proceeding under any reorganization, arrangement, adjustment
of debt, relief of debtors, dissolution, insolvency or liquidation or similar
law of any jurisdiction whether now or hereafter in effect relating to the
Obligor or any subsidiary of the Obligor or there is commenced against the
Obligor or any subsidiary of the Obligor any such bankruptcy, insolvency or
other proceeding which remains undismissed for a period of 61 days; or the
Obligor or any subsidiary of the Obligor is adjudicated insolvent or bankrupt;
or any order of relief or other order approving any such case or proceeding is
entered; or the Obligor or any subsidiary of the Obligor suffers any appointment
of any custodian, private or court appointed receiver or the like for it or any
substantial part of its property which continues undischarged or unstayed for a
period of sixty one (61) days; or the Obligor or any subsidiary of the Obligor
makes a general assignment for the benefit of creditors; or the Obligor or any
subsidiary of the Obligor shall fail to pay, or shall state that it is unable to
pay, or shall be unable to pay, its debts generally as they become due; or the
Obligor or any subsidiary of the Obligor shall call a meeting of its creditors
with a view to arranging a composition, adjustment or restructuring of its
debts; or the Obligor or any subsidiary of the Obligor shall by any act or
failure to act expressly indicate its consent to, approval of or acquiescence in
any of the foregoing; or any corporate or other action is taken by the Obligor
or any subsidiary of the Obligor for the purpose of effecting any of the
foregoing;

            (iv) The Obligor or any subsidiary of the Obligor shall default in
any of its obligations under any other debenture or any mortgage, credit
agreement or other facility, indenture agreement, factoring agreement or other
instrument under which there may be issued, or by which there may be secured or
evidenced any indebtedness for borrowed money or money due under any long term
leasing or factoring arrangement of the Obligor or any subsidiary of the Obligor
in an amount exceeding $100,000, whether such indebtedness now exists or shall
hereafter be created and such default shall result in such indebtedness becoming
or being declared due and payable prior to the date on which it would otherwise
become due and payable;

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            (v) The Common Stock shall cease to be quoted for trading or listed
for trading on either the Nasdaq OTC Bulletin Board ("OTC"), Nasdaq SmallCap
Market, New York Stock Exchange, American Stock Exchange or the Nasdaq National
Market (each, a "Subsequent Market") and shall not again be quoted or listed for
trading thereon within five (5) Trading Days of such delisting;

            (vi) The Obligor or any subsidiary of the Obligor shall be a party
to any Change of Control Transaction (as defined in Section 4);

            (vii) The Obligor shall fail to file the Underlying Shares
Registration Statement (as defined in Section 4) with the Commission (as defined
in Section 4), or the Underlying Shares Registration Statement shall not have
been declared effective by the Commission, in each case within the time periods
set forth in the Registration Rights Agreement of even date herewith between the
Obligor and the Holder;

            (viii) If the effectiveness of the Underlying Shares Registration
Statement lapses for any reason or the Holder shall not be permitted to resell
the shares of Common Stock underlying this Debenture under the Underlying Shares
Registration Statement, in either case, for more than five (5) consecutive
Trading Days or an aggregate of eight Trading Days (which need not be
consecutive Trading Days);

            (ix) The Obligor shall fail for any reason to deliver Common Stock
certificates to a Holder prior to the fifth (5th) Trading Day after a Conversion
Date or the Obligor shall provide notice to the Holder, including by way of
public announcement, at any time, of its intention not to comply with requests
for conversions of this Debenture in accordance with the terms hereof;

            (x) The Obligor shall fail for any reason to deliver the payment in
cash pursuant to a Buy-In (as defined herein) within fifteen (15) days after
notice is claimed delivered hereunder;

      (b) During the time that any portion of this Debenture is outstanding, if
any Event of Default has occurred, the full principal amount of this Debenture,
together with interest and other amounts owing in respect thereof, to the date
of acceleration shall become at the Holder's election, immediately due and
payable in cash, provided however, the Holder may request (but shall have no
obligation to request) payment of such amounts in Common Stock of the Obligor.
If an Event of Default occurs and remains uncured, the Conversion Price shall be
reduced to Ten Cents ($0.10). In addition to any other remedies, the Holder
shall have the right (but not the obligation) to convert this Debenture at any
time after (x) an Event of Default or (y) the Maturity Date at the Conversion
Price then in-effect. The Holder need not provide and the Obligor hereby waives
any presentment, demand, protest or other notice of any kind, and the Holder may
immediately and without expiration of any grace period enforce any and all of
its rights and remedies hereunder and all other remedies available to it under
applicable law. Such declaration may be rescinded and annulled by Holder at any

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time prior to payment hereunder. No such rescission or annulment shall affect
any subsequent Event of Default or impair any right consequent thereon. Upon an
Event of Default, notwithstanding any other provision of this Debenture or any
Transaction Document, the Holder shall have no obligation to comply with or
adhere to any limitations, if any, on the conversion of this Debenture or the
sale of the Underlying Shares.

      Section 3. Conversion.

      (a) (i) Conversion at Option of Holder.

            (A) This Debenture shall be convertible into shares of Common Stock
at the option of the Holder, in whole or in part at any time and from time to
time, after the Original Issue Date (as defined in Section 4) (subject to the
limitations on conversion set forth in Section 3(a)(ii) hereof). The number of
shares of Common Stock issuable upon a conversion hereunder equals the quotient
obtained by dividing (x) the outstanding amount of this Debenture to be
converted by (y) the Conversion Price (as defined in Section 3(c)(i)). The
Obligor shall deliver Common Stock certificates to the Holder prior to the Fifth
(5th) Trading Day after a Conversion Date.

            (B) Notwithstanding anything to the contrary contained herein, if on
any Conversion Date: (1) the number of shares of Common Stock at the time
authorized, unissued and unreserved for all purposes, or held as treasury stock,
is insufficient to pay principal and interest hereunder in shares of Common
Stock; (2) the Common Stock is not listed or quoted for trading on the OTC or on
a Subsequent Market; (3) the Obligor has failed to timely satisfy its
conversion; or (4) the issuance of such shares of Common Stock would result in a
violation of Section 3(a)(ii), then, at the option of the Holder, the Obligor,
in lieu of delivering shares of Common Stock pursuant to Section 3(a)(i)(A),
shall deliver, within three (3) Trading Days of each applicable Conversion Date,
an amount in cash equal to the product of the outstanding principal amount to be
converted plus any interest due therein divided by the Conversion Price and
multiplied by the highest closing price of the stock from date of the conversion
notice till the date that such cash payment is made.

      Further, if the Obligor shall not have delivered any cash due in respect
of conversion of this Debenture or as payment of interest thereon by the fifth
(5th) Trading Day after the Conversion Date, the Holder may, by notice to the
Obligor, require the Obligor to issue shares of Common Stock pursuant to Section
3(c), except that for such purpose the Conversion Price applicable thereto shall
be the lesser of the Conversion Price on the Conversion Date and the Conversion
Price on the date of such Holder demand. Any such shares will be subject to the
provisions of this Section.

            (C) The Holder shall effect conversions by delivering to the Obligor
a completed notice in the form attached hereto as Exhibit A (a "Conversion
Notice"). The date on which a Conversion Notice is delivered is the "Conversion
Date." Unless the Holder is converting the entire principal amount outstanding
under this Debenture, the Holder is not required to physically surrender this
Debenture to the Obligor in order to effect conversions. Conversions hereunder
shall have the effect of lowering the outstanding principal amount of this
Debenture plus all accrued and unpaid interest thereon in an amount equal to the
applicable conversion. The Holder and the Obligor shall maintain records showing
the principal amount converted and the date of such conversions. In the event of
any dispute or discrepancy, the records of the Holder shall be controlling and
determinative in the absence of manifest error.

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            (ii) Certain Conversion Restrictions.

                  (A) A Holder may not convert this Debenture or receive shares
of Common Stock as payment of interest hereunder to the extent such conversion
or receipt of such interest payment would result in the Holder, together with
any affiliate thereof, beneficially owning (as determined in accordance with
Section 13(d) of the Exchange Act and the rules promulgated thereunder) in
excess of 4.9% of the then issued and outstanding shares of Common Stock,
including shares issuable upon conversion of, and payment of interest on, this
Debenture held by such Holder after application of this Section. Since the
Holder will not be obligated to report to the Obligor the number of shares of
Common Stock it may hold at the time of a conversion hereunder, unless the
conversion at issue would result in the issuance of shares of Common Stock in
excess of 4.9% of the then outstanding shares of Common Stock without regard to
any other shares which may be beneficially owned by the Holder or an affiliate
thereof, the Holder shall have the authority and obligation to determine whether
the restriction contained in this Section will limit any particular conversion
hereunder and to the extent that the Holder determines that the limitation
contained in this Section applies, the determination of which portion of the
principal amount of this Debenture is convertible shall be the responsibility
and obligation of the Holder. If the Holder has delivered a Conversion Notice
for a principal amount of this Debenture that, without regard to any other
shares that the Holder or its affiliates may beneficially own, would result in
the issuance in excess of the permitted amount hereunder, the Obligor shall
notify the Holder of this fact and shall honor the conversion for the maximum
principal amount permitted to be converted on such Conversion Date in accordance
with the periods described in Section 3(a)(i)(A) and, at the option of the
Holder, either retain any principal amount tendered for conversion in excess of
the permitted amount hereunder for future conversions or return such excess
principal amount to the Holder. The provisions of this Section may be waived by
a Holder (but only as to itself and not to any other Holder) upon not less than
65 days prior notice to the Obligor. Other Holders shall be unaffected by any
such waiver.

      (b) (i) Nothing herein shall limit a Holder's right to pursue actual
damages or declare an Event of Default pursuant to Section 2 herein for the
Obligor 's failure to deliver certificates representing shares of Common Stock
upon conversion within the period specified herein and such Holder shall have
the right to pursue all remedies available to it at law or in equity including,
without limitation, a decree of specific performance and/or injunctive relief,
in each case without the need to post a bond or provide other security. The
exercise of any such rights shall not prohibit the Holder from seeking to
enforce damages pursuant to any other Section hereof or under applicable law.

            (ii) In addition to any other rights available to the Holder, if the
Obligor fails to deliver to the Holder such certificate or certificates pursuant
to Section 3(a)(i)(A) by the fifth (5th) Trading Day after the Conversion Date,
and if after such fifth (5th) Trading Day the Holder purchases (in an open
market transaction or otherwise) Common Stock to deliver in satisfaction of a
sale by such Holder of the Underlying Shares which the Holder anticipated
receiving upon such conversion (a "Buy-In"), then the Obligor shall (A) pay in

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cash to the Holder (in addition to any remedies available to or elected by the
Holder) the amount by which (x) the Holder's total purchase price (including
brokerage commissions, if any) for the Common Stock so purchased exceeds (y) the
product of (1) the aggregate number of shares of Common Stock that such Holder
anticipated receiving from the conversion at issue multiplied by (2) the market
price of the Common Stock at the time of the sale giving rise to such purchase
obligation and (B) at the option of the Holder, either reissue a Debenture in
the principal amount equal to the principal amount of the attempted conversion
or deliver to the Holder the number of shares of Common Stock that would have
been issued had the Obligor timely complied with its delivery requirements under
Section 3(a)(i)(A). For example, if the Holder purchases Common Stock having a
total purchase price of $11,000 to cover a Buy-In with respect to an attempted
conversion of Debentures with respect to which the market price of the
Underlying Shares on the date of conversion was a total of $10,000 under clause
(A) of the immediately preceding sentence, the Obligor shall be required to pay
the Holder $1,000. The Holder shall provide the Obligor written notice
indicating the amounts payable to the Holder in respect of the Buy-In.

      (c) (i) The Holder is entitled, at its option, to convert, and sell on the
same day, at any time, until payment in full of this Debenture, all or any part
of the principal amount of the Debenture, plus accrued interest, into shares of
the Company's common stock, par value $0.001 per share, at the price per share
equal to the lesser of (a) an amount equal to One Dollar ($1.00) (the "Fixed
Price") or (b) an amount equal to ninety five percent (95%) of the lowest
Closing Bid Price of the Common Stock for the thirty (30) trading days
immediately preceding the Conversion Date (the "Closing Bid Conversion Price")
which may be adjusted pursuant to the other terms of this Debenture.
Subparagraphs (a) and (b) above are individually referred to as a "Conversion
Price." Notwithstanding the foregoing, the Holder shall limit conversion of this
Debenture to $250,000 per calendar month for so long as no Event of Default has
occurred hereunder only if the Holder coverts pursuant to the Closing Bid
Conversion Price under this Section. Such limitation on conversion shall not
apply if the Holder coverts pursuant to the Fixed Price.

            (ii) If the Obligor, at any time while this Debenture is
outstanding, shall (a) pay a stock dividend or otherwise make a distribution or
distributions on shares of its Common Stock or any other equity or equity
equivalent securities payable in shares of Common Stock, (b) subdivide
outstanding shares of Common Stock into a larger number of shares, (c) combine
(including by way of reverse stock split) outstanding shares of Common Stock
into a smaller number of shares, or (d) issue by reclassification of shares of
the Common Stock any shares of capital stock of the Obligor, then the Fixed
Price shall be multiplied by a fraction of which the numerator shall be the
number of shares of Common Stock (excluding treasury shares, if any) outstanding
before such event and of which the denominator shall be the number of shares of
Common Stock outstanding after such event. Any adjustment made pursuant to this
Section shall become effective immediately after the record date for the
determination of stockholders entitled to receive such dividend or distribution
and shall become effective immediately after the effective date in the case of a
subdivision, combination or re-classification.

            (iii) If the Obligor, at any time while this Debenture is
outstanding, shall issue rights, options or warrants to all holders of Common
Stock (and not to the Holder) entitling them to subscribe for or purchase shares
of Common Stock at a price per share less than the Fixed Price, then the Fixed
Price shall be multiplied by a fraction, of which the denominator shall be the
number of shares of the Common Stock (excluding treasury shares, if any)
outstanding on the date of issuance of such rights or warrants (plus the number

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of additional shares of Common Stock offered for subscription or purchase), and
of which the numerator shall be the number of shares of the Common Stock
(excluding treasury shares, if any) outstanding on the date of issuance of such
rights or warrants, plus the number of shares which the aggregate offering price
of the total number of shares so offered would purchase at the Fixed Price. Such
adjustment shall be made whenever such rights or warrants are issued, and shall
become effective immediately after the record date for the determination of
stockholders entitled to receive such rights, options or warrants. However, upon
the expiration of any such right, option or warrant to purchase shares of the
Common Stock the issuance of which resulted in an adjustment in the Fixed Price
pursuant to this Section, if any such right, option or warrant shall expire and
shall not have been exercised, the Fixed Price shall immediately upon such
expiration be recomputed and effective immediately upon such expiration be
increased to the price which it would have been (but reflecting any other
adjustments in the Fixed Price made pursuant to the provisions of this Section
after the issuance of such rights or warrants) had the adjustment of the Fixed
Price made upon the issuance of such rights, options or warrants been made on
the basis of offering for subscription or purchase only that number of shares of
the Common Stock actually purchased upon the exercise of such rights, options or
warrants actually exercised.

            (iv) If the Obligor or any subsidiary thereof, as applicable, at any
time while this Debenture is outstanding, shall issue shares of Common Stock or
rights, warrants, options or other securities or debt that are convertible into
or exchangeable for shares of Common Stock ("Common Stock Equivalents")
entitling any Person to acquire shares of Common Stock, at a price per share
less than the Fixed Price (if the holder of the Common Stock or Common Stock
Equivalent so issued shall at any time, whether by operation of purchase price
adjustments, reset provisions, floating conversion, exercise or exchange prices
or otherwise, or due to warrants, options or rights per share which is issued in
connection with such issuance, be entitled to receive shares of Common Stock at
a price per share which is less than the Fixed Price, such issuance shall be
deemed to have occurred for less than the Fixed Price), then, at the sole option
of the Holder, the Fixed Price shall be adjusted to mirror the conversion,
exchange or purchase price for such Common Stock or Common Stock Equivalents
(including any reset provisions thereof) at issue. Such adjustment shall be made
whenever such Common Stock or Common Stock Equivalents are issued. The Obligor
shall notify the Holder in writing, no later than one (1) business day following
the issuance of any Common Stock or Common Stock Equivalent subject to this
Section, indicating therein the applicable issuance price, or of applicable
reset price, exchange price, conversion price and other pricing terms. No
adjustment under this Section shall be made as a result of issuances and
exercises of options to purchase shares of Common Stock issued for compensatory
purposes pursuant to any of the Obligor's stock option or stock purchase plans.

            (v) If the Obligor, at any time while this Debenture is outstanding,
shall distribute to all holders of Common Stock (and not to the Holder)
evidences of its indebtedness or assets or rights or warrants to subscribe for
or purchase any security, then in each such case the Fixed Price at which this
Debenture shall thereafter be convertible shall be determined by multiplying the
Fixed Price in effect immediately prior to the record date fixed for
determination of stockholders entitled to receive such distribution by a
fraction of which the denominator shall be the Closing Bid Price determined as

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of the record date mentioned above, and of which the numerator shall be such
Closing Bid Price on such record date less the then fair market value at such
record date of the portion of such assets or evidence of indebtedness so
distributed applicable to one outstanding share of the Common Stock as
determined by the Board of Directors in good faith. In either case the
adjustments shall be described in a statement provided to the Holder of the
portion of assets or evidences of indebtedness so distributed or such
subscription rights applicable to one share of Common Stock. Such adjustment
shall be made whenever any such distribution is made and shall become effective
immediately after the record date mentioned above.

            (vi) In case of any reclassification of the Common Stock or any
compulsory share exchange pursuant to which the Common Stock is converted into
other securities, cash or property, the Holder shall have the right thereafter
to, at its option, (A) convert the then outstanding principal amount, together
with all accrued but unpaid interest and any other amounts then owing hereunder
in respect of this Debenture into the shares of stock and other securities, cash
and property receivable upon or deemed to be held by holders of the Common Stock
following such reclassification or share exchange, and the Holder of this
Debenture shall be entitled upon such event to receive such amount of
securities, cash or property as the shares of the Common Stock of the Obligor
into which the then outstanding principal amount, together with all accrued but
unpaid interest and any other amounts then owing hereunder in respect of this
Debenture could have been converted immediately prior to such reclassification
or share exchange would have been entitled, or (B) require the Obligor to prepay
the outstanding principal amount of this Debenture, plus all interest and other
amounts due and payable thereon. The entire prepayment price shall be paid in
cash. This provision shall similarly apply to successive reclassifications or
share exchanges.

            (vii) The Obligor shall maintain a share reserve of not less than
one hundred percent (100%) of the shares of Common Stock issuable upon
conversion of this Debenture; and within three (3) Business Days following the
receipt by the Obligor of a Holder's notice that such minimum number of
Underlying Shares is not so reserved, the Obligor shall promptly reserve a
sufficient number of shares of Common Stock to comply with such requirement.

            (viii) All calculations under this Section 3 shall be rounded up to
the nearest $0.001 of a share.

            (ix) Whenever the Fixed Price is adjusted pursuant to Section 3
hereof, the Obligor shall promptly mail to the Holder a notice setting forth the
Fixed Price after such adjustment and setting forth a brief statement of the
facts requiring such adjustment.

            (x) If (A) the Obligor shall declare a dividend (or any other
distribution) on the Common Stock; (B) the Obligor shall declare a special
nonrecurring cash dividend on or a redemption of the Common Stock; (C) the
Obligor shall authorize the granting to all holders of the Common Stock rights
or warrants to subscribe for or purchase any shares of capital stock of any
class or of any rights; (D) the approval of any stockholders of the Obligor
shall be required in connection with any reclassification of the Common Stock,
any consolidation or merger to which the Obligor is a party, any sale or
transfer of all or substantially all of the assets of the Obligor, of any
compulsory share exchange whereby the Common Stock is converted into other
securities, cash or property; or (E) the Obligor shall authorize the voluntary

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or involuntary dissolution, liquidation or winding up of the affairs of the
Obligor; then, in each case, the Obligor shall cause to be filed at each office
or agency maintained for the purpose of conversion of this Debenture, and shall
cause to be mailed to the Holder at its last address as it shall appear upon the
stock books of the Obligor, at least twenty (20) calendar days prior to the
applicable record or effective date hereinafter specified, a notice stating (x)
the date on which a record is to be taken for the purpose of such dividend,
distribution, redemption, rights or warrants, or if a record is not to be taken,
the date as of which the holders of the Common Stock of record to be entitled to
such dividend, distributions, redemption, rights or warrants are to be
determined or (y) the date on which such reclassification, consolidation,
merger, sale, transfer or share exchange is expected to become effective or
close, and the date as of which it is expected that holders of the Common Stock
of record shall be entitled to exchange their shares of the Common Stock for
securities, cash or other property deliverable upon such reclassification,
consolidation, merger, sale, transfer or share exchange, provided, that the
failure to mail such notice or any defect therein or in the mailing thereof
shall not affect the validity of the corporate action required to be specified
in such notice. The Holder is entitled to convert this Debenture during the
20-day calendar period commencing the date of such notice to the effective date
of the event triggering such notice.

            (xi) In case of any (1) merger or consolidation of the Obligor or
any subsidiary of the Obligor with or into another Person, or (2) sale by the
Obligor or any subsidiary of the Obligor of more than one-half of the assets of
the Obligor in one or a series of related transactions, a Holder shall have the
right to (A) exercise any rights under Section 2(b), (B) convert the aggregate
amount of this Debenture then outstanding into the shares of stock and other
securities, cash and property receivable upon or deemed to be held by holders of
Common Stock following such merger, consolidation or sale, and such Holder shall
be entitled upon such event or series of related events to receive such amount
of securities, cash and property as the shares of Common Stock into which such
aggregate principal amount of this Debenture could have been converted
immediately prior to such merger, consolidation or sales would have been
entitled, or (C) in the case of a merger or consolidation, require the surviving
entity to issue to the Holder a convertible Debenture with a principal amount
equal to the aggregate principal amount of this Debenture then held by such
Holder, plus all accrued and unpaid interest and other amounts owing thereon,
which such newly issued convertible Debenture shall have terms identical
(including with respect to conversion) to the terms of this Debenture, and shall
be entitled to all of the rights and privileges of the Holder of this Debenture
set forth herein and the agreements pursuant to which this Debentures were
issued. In the case of clause (C), the conversion price applicable for the newly
issued shares of convertible preferred stock or convertible Debentures shall be
based upon the amount of securities, cash and property that each share of Common
Stock would receive in such transaction and the Conversion Price in effect
immediately prior to the effectiveness or closing date for such transaction. The
terms of any such merger, sale or consolidation shall include such terms so as
to continue to give the Holder the right to receive the securities, cash and
property set forth in this Section upon any conversion or redemption following
such event. This provision shall similarly apply to successive such events.

      (d) The Obligor covenants that it will at all times reserve and keep
available out of its authorized and unissued shares of Common Stock solely for
the purpose of issuance upon conversion of this Debenture and payment of
interest on this Debenture, each as herein provided, free from preemptive rights
or any other actual contingent purchase rights of persons other than the Holder,

                                       10
<PAGE>

not less than such number of shares of the Common Stock as shall (subject to any
additional requirements of the Obligor as to reservation of such shares set
forth in this Debenture) be issuable (taking into account the adjustments and
restrictions of Sections 2(b) and 3(c)) upon the conversion of the outstanding
principal amount of this Debenture and payment of interest hereunder. The
Obligor covenants that all shares of Common Stock that shall be so issuable
shall, upon issue, be duly and validly authorized, issued and fully paid,
nonassessable and, if the Underlying Shares Registration Statement has been
declared effective under the Securities Act, registered for public sale in
accordance with such Underlying Shares Registration Statement.

      (e) Upon a conversion hereunder the Obligor shall not be required to issue
stock certificates representing fractions of shares of the Common Stock, but may
if otherwise permitted, make a cash payment in respect of any final fraction of
a share based on the Closing Bid Price at such time. If the Obligor elects not,
or is unable, to make such a cash payment, the Holder shall be entitled to
receive, in lieu of the final fraction of a share, one whole share of Common
Stock.

      (f) The issuance of certificates for shares of the Common Stock on
conversion of this Debenture shall be made without charge to the Holder thereof
for any documentary stamp or similar taxes that may be payable in respect of the
issue or delivery of such certificate, provided that the Obligor shall not be
required to pay any tax that may be payable in respect of any transfer involved
in the issuance and delivery of any such certificate upon conversion in a name
other than that of the Holder of such Debenture so converted and the Obligor
shall not be required to issue or deliver such certificates unless or until the
person or persons requesting the issuance thereof shall have paid to the Obligor
the amount of such tax or shall have established to the satisfaction of the
Obligor that such tax has been paid.

      (g) Any notices, consents, waivers or other communications required or
permitted to be given under the terms hereof must be in writing and will be
deemed to have been delivered: (i) upon receipt, when delivered personally; (ii)
upon receipt, when sent by facsimile (provided confirmation of transmission is
mechanically or electronically generated and kept on file by the sending party);
or (iii) one (1) trading day after deposit with a nationally recognized
overnight delivery service, in each case properly addressed to the party to
receive the same. The addresses and facsimile numbers for such communications
shall be:

If to the Company, to:           NetFabric Holdings, Inc.
                                 67 Federal Road, Building A
                                 Suite 300
                                 Brookfield, CT 06804
                                 Telephone: (203) 775-1178
                                 Facsimile: (270) 626-8366

With a copy to:                  Kirkpatrick & Lockhart Nicholson Graham LLP
                                 201 South Biscayne Boulevard, Suite 2000
                                 Miami, Florida 33131
                                 Attention: Clayton E. Parker, Esq.
                                 Telephone: (305) 539-3306
                                 Facsimile: (305) 328-7095

                                       11
<PAGE>

If to the Holder:                Cornell Capital Partners, LP
                                 101 Hudson Street, Suite 3700
                                 Jersey City, NJ 07303
                                 Attention: Mark Angelo
                                 Telephone: (201) 985-8300

With a copy to:                  Troy Rillo, Esq.
                                 101 Hudson Street - Suite 3700
                                 Jersey City, NJ 07302
                                 Telephone: (201) 985-8300
                                 Facsimile: (201) 985-8266

or at such other address and/or facsimile number and/or to the attention of such
other person as the recipient party has specified by written notice given to
each other party three (3) business days prior to the effectiveness of such
change. Written confirmation of receipt (i) given by the recipient of such
notice, consent, waiver or other communication, (ii) mechanically or
electronically generated by the sender's facsimile machine containing the time,
date, recipient facsimile number and an image of the first page of such
transmission or (iii) provided by a nationally recognized overnight delivery
service, shall be rebuttable evidence of personal service, receipt by facsimile
or receipt from a nationally recognized overnight delivery service in accordance
with clause (i), (ii) or (iii) above, respectively.

      Section 4. Definitions. For the purposes hereof, the following terms shall
have the following meanings:

      "Business Day" means any day except Saturday, Sunday and any day which
shall be a federal legal holiday in the United States or a day on which banking
institutions are authorized or required by law or other government action to
close.

      "Change of Control Transaction" means the occurrence of (a) an acquisition
after the date hereof by an individual or legal entity or "group" (as described
in Rule 13d-5(b)(1) promulgated under the Exchange Act) of effective control
(whether through legal or beneficial ownership of capital stock of the Obligor,
by contract or otherwise) of in excess of fifty percent (50%) of the voting
securities of the Obligor (except that the acquisition of voting securities by
the Holder shall not constitute a Change of Control Transaction for purposes
hereof), (b) a replacement at one time or over time of more than one-half of the
members of the board of directors of the Obligor which is not approved by a
majority of those individuals who are members of the board of directors on the
date hereof (or by those individuals who are serving as members of the board of
directors on any date whose nomination to the board of directors was approved by

                                       12
<PAGE>

a majority of the members of the board of directors who are members on the date
hereof), (c) the merger, consolidation or sale of fifty percent (50%) or more of
the assets of the Obligor or any subsidiary of the Obligor in one or a series of
related transactions with or into another entity, or (d) the execution by the
Obligor of an agreement to which the Obligor is a party or by which it is bound,
providing for any of the events set forth above in (a), (b) or (c).

      "Commission" means the Securities and Exchange Commission.

      "Common Stock" means the common stock, par value $0.001, of the Obligor
and stock of any other class into which such shares may hereafter be changed or
reclassified.

      "Conversion Date" shall mean the date upon which the Holder gives the
Obligor notice of their intention to effectuate a conversion of this Debenture
into shares of the Company's Common Stock as outlined herein.

      "Exchange Act" means the Securities Exchange Act of 1934, as amended.

      "Original Issue Date" shall mean the date of the first issuance of this
Debenture regardless of the number of transfers and regardless of the number of
instruments, which may be issued to evidence such Debenture.

      "Closing Bid Price" means the price per share in the last reported trade
of the Common Stock on the OTC or on the exchange which the Common Stock is then
listed as quoted by Bloomberg, LP.

      "Person" means a corporation, an association, a partnership, organization,
a business, an individual, a government or political subdivision thereof or a
governmental agency.

      "Securities Act" means the Securities Act of 1933, as amended, and the
rules and regulations promulgated thereunder.

      "Trading Day" means a day on which the shares of Common Stock are quoted
on the OTC or quoted or traded on such Subsequent Market on which the shares of
Common Stock are then quoted or listed; provided, that in the event that the
shares of Common Stock are not listed or quoted, then Trading Day shall mean a
Business Day.

      "Transaction Documents" means the Securities Purchase Agreement or any
other agreement delivered in connection with the Securities Purchase Agreement,
including, without limitation, the Officer's Pledge Agreement, the Amended and
Restated Security Agreement, the Amended and Restated Subsidiary Security
Agreements, the Investor Registration Rights Agreement, the Escrow Agreement,
the Irrevocable Transfer Agent Instructions and the Warrant.

      "Underlying Shares" means the shares of Common Stock issuable upon
conversion of this Debenture or as payment of interest in accordance with the
terms hereof.

      "Underlying Shares Registration Statement" means a registration statement
meeting the requirements set forth in the Registration Rights Agreement,
covering among other things the resale of the Underlying Shares and naming the
Holder as a "selling stockholder" thereunder.

                                       13
<PAGE>

      Section 5. Except as expressly provided herein, no provision of this
Debenture shall alter or impair the obligations of the Obligor, which are
absolute and unconditional, to pay the principal of, interest and other charges
(if any) on, this Debenture at the time, place, and rate, and in the coin or
currency, herein prescribed. This Debenture is a direct obligation of the
Obligor. This Debenture ranks pari passu with all other Debentures now or
hereafter issued under the terms set forth herein. As long as this Debenture is
outstanding, the Obligor shall not and shall cause their subsidiaries not to,
without the consent of the Holder, (i) amend its certificate of incorporation,
bylaws or other charter documents so as to adversely affect any rights of the
Holder; (ii) repay, repurchase or offer to repay, repurchase or otherwise
acquire shares of its Common Stock or other equity securities other than as to
the Underlying Shares to the extent permitted or required under the Transaction
Documents; or (iii) enter into any agreement with respect to any of the
foregoing.

      Section 6. This Debenture shall not entitle the Holder to any of the
rights of a stockholder of the Obligor, including without limitation, the right
to vote, to receive dividends and other distributions, or to receive any notice
of, or to attend, meetings of stockholders or any other proceedings of the
Obligor, unless and to the extent converted into shares of Common Stock in
accordance with the terms hereof.

      Section 7. If this Debenture is mutilated, lost, stolen or destroyed, the
Obligor shall execute and deliver, in exchange and substitution for and upon
cancellation of the mutilated Debenture, or in lieu of or in substitution for a
lost, stolen or destroyed Debenture, a new Debenture for the principal amount of
this Debenture so mutilated, lost, stolen or destroyed but only upon receipt of
evidence of such loss, theft or destruction of such Debenture, and of the
ownership hereof, and indemnity, if requested, all reasonably satisfactory to
the Obligor.

      Section 8. No indebtedness of the Obligor is senior to this Debenture in
right of payment, whether with respect to interest, damages or upon liquidation
or dissolution or otherwise. Without the Holder's consent, the Obligor will not
and will not permit any of their subsidiaries to, directly or indirectly, enter
into, create, incur, assume or suffer to exist any indebtedness of any kind, on
or with respect to any of its property or assets now owned or hereafter acquired
or any interest therein or any income or profits there from that is senior in
any respect to the obligations of the Obligor under this Debenture.

      Section 9. This Debenture shall be governed by and construed in accordance
with the laws of the State of New Jersey, without giving effect to conflicts of
laws thereof. Each of the parties consents to the jurisdiction of the Superior
Courts of the State of New Jersey sitting in Hudson County, New Jersey and the
U.S. District Court for the District of New Jersey sitting in Newark, New Jersey
in connection with any dispute arising under this Debenture and hereby waives,
to the maximum extent permitted by law, any objection, including any objection
based on forum non conveniens to the bringing of any such proceeding in such
jurisdictions.

      Section 10. If the Obligor fails to strictly comply with the terms of this
Debenture, then the Obligor shall reimburse the Holder promptly for all fees,
costs and expenses, including, without limitation, attorneys' fees and expenses
incurred by the Holder in any action in connection with this Debenture,
including, without limitation, those incurred: (i) during any workout, attempted
workout, and/or in connection with the rendering of legal advice as to the
Holder's rights, remedies and obligations, (ii) collecting any sums which become
due to the Holder, (iii) defending or prosecuting any proceeding or any
counterclaim to any proceeding or appeal; or (iv) the protection, preservation
or enforcement of any rights or remedies of the Holder.

                                       14
<PAGE>

      Section 11. Any waiver by the Holder of a breach of any provision of this
Debenture shall not operate as or be construed to be a waiver of any other
breach of such provision or of any breach of any other provision of this
Debenture. The failure of the Holder to insist upon strict adherence to any term
of this Debenture on one or more occasions shall not be considered a waiver or
deprive that party of the right thereafter to insist upon strict adherence to
that term or any other term of this Debenture. Any waiver must be in writing.

      Section 12. If any provision of this Debenture is invalid, illegal or
unenforceable, the balance of this Debenture shall remain in effect, and if any
provision is inapplicable to any person or circumstance, it shall nevertheless
remain applicable to all other persons and circumstances. If it shall be found
that any interest or other amount deemed interest due hereunder shall violate
applicable laws governing usury, the applicable rate of interest due hereunder
shall automatically be lowered to equal the maximum permitted rate of interest.
The Obligor covenants (to the extent that it may lawfully do so) that it shall
not at any time insist upon, plead, or in any manner whatsoever claim or take
the benefit or advantage of, any stay, extension or usury law or other law which
would prohibit or forgive the Obligor from paying all or any portion of the
principal of or interest on this Debenture as contemplated herein, wherever
enacted, now or at any time hereafter in force, or which may affect the
covenants or the performance of this indenture, and the Obligor (to the extent
it may lawfully do so) hereby expressly waives all benefits or advantage of any
such law, and covenants that it will not, by resort to any such law, hinder,
delay or impeded the execution of any power herein granted to the Holder, but
will suffer and permit the execution of every such as though no such law has
been enacted.

      Section 13. Whenever any payment or other obligation hereunder shall be
due on a day other than a Business Day, such payment shall be made on the next
succeeding Business Day.

      Section 14. THE PARTIES HEREBY KNOWINGLY, VOLUNTARILY AND INTENTIONALLY
WAIVE THE RIGHT ANY OF THEM MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY
LITIGATION BASED HEREON OR ARISING OUT OF, UNDER OR IN CONNECTION WITH THIS
AGREEMENT OR ANY TRANSACTION DOCUMENT OR ANY COURSE OF CONDUCT, COURSE OF
DEALING, STATEMENTS (WHETHER VERBAL OR WRITTEN) OR ACTIONS OF ANY PARTY. THIS
PROVISION IS A MATERIAL INDUCEMENT FOR THE PARTIES' ACCEPTANCE OF THIS
AGREEMENT.

                   [REMAINDER OF PAGE INTENTIONLLY LEFT BLANK]

                                       15
<PAGE>

      IN WITNESS WHEREOF, the Obligor has caused this Secured Convertible
Debenture to be duly executed by a duly authorized officer as of the date set
forth above.

                                        NETFABRIC HOLDINGS, INC.

                                        By:  /s/ Jeff Robinson
                                            ------------------------------------
                                        Name:  Jeff Robinson
                                        Title: Chairman and Chief Executive
                                               Officer

                                       16
<PAGE>

                                   EXHIBIT "A"

                              NOTICE OF CONVERSION

        (TO BE EXECUTED BY THE HOLDER IN ORDER TO CONVERT THE DEBENTURE)

TO:

      The undersigned hereby irrevocably elects to convert $ of the principal
amount of the above Debenture into Shares of Common Stock of NetFabric Holdings,
Inc., according to the conditions stated therein, as of the Conversion Date
written below.

CONVERSION DATE:                           _____________________________________

APPLICABLE CONVERSION PRICE:               _____________________________________

SIGNATURE:                                 _____________________________________

NAME:                                      _____________________________________

ADDRESS:                                   _____________________________________

AMOUNT TO BE CONVERTED:                    $____________________________________

AMOUNT OF DEBENTURE UNCONVERTED:           $____________________________________

CONVERSION PRICE PER SHARE:                $____________________________________

NUMBER OF SHARES OF COMMON STOCK TO BE
ISSUED:                                    _____________________________________

PLEASE ISSUE THE SHARES OF COMMON
STOCK IN THE FOLLOWING NAME AND
TO THE FOLLOWING ADDRESS:                  _____________________________________

ISSUE TO:                                  _____________________________________

AUTHORIZED SIGNATURE:                      _____________________________________

NAME:                                      _____________________________________

TITLE:                                     _____________________________________

PHONE NUMBER:                              _____________________________________

BROKER DTC PARTICIPANT CODE:               _____________________________________

ACCOUNT NUMBER:                            _____________________________________Amended and Restated Bridge Loan Promissory Note

$10,353,492                                                    September 1, 2005

      FOR VALUE RECEIVED, GRAN TIERRA ENERGY INC., an Alberta corporation
(hereinafter called the "Borrower"), hereby promises to pay to the order of
GOLDSTRIKE INC., a Nevada corporation (hereinafter called the "Lender"), c/o
Gottbetter & Partners LLP, 488 Madison Avenue, 12th Floor, New York, New York
10022, the principal sum of Ten Million Three Hundred Fifty Three Thousand Four
Hundred Ninety Two Dollars ($10,353,492) (the "Commitment"), or so much thereof
as shall have been borrowed by Borrower during the 120-day period following the
date of this Note as set forth on Schedule A attached hereto and made a part
hereof, in lawful money of the United States of America and in immediately
available funds.

      1. The outstanding principal balance of this Note, together with accrued
and unpaid interest thereon, shall be due and payable no later than the earlier
of (i) December 30, 2005 and (ii) the date of closing of the Merger, as
contemplated by the Term Sheet. The date such repayment is due is sometimes
referred to as the "Due Date." Upon the closing of the Merger, all indebtedness
evidenced hereby shall be deemed canceled and paid in full.

      2. This Note shall bear interest at the rate of nine percent (9%) per
annum on (i) for the period from September 1 through October 6, 2005, the sum of
Eight Million Three Hundred Thirty Seven Thousand Nine Hundred Sixteen Dollars
($8,337,916), (ii) for the period from October 7, 2005 through October 27, 2005,
the sum of Nine Million Three Hundred Fifty Three Thousand Four Hundred Ninety
Two Dollars ($9,353,492) and (iii) from and after October 28, 2005, the amount
of the entire Commitment, regardless of the actual amount borrowed by Borrower
hereunder as set forth on Schedule A hereto. Interest shall be calculated on the
basis of a year of three hundred sixty (360) days applied to the actual days on
which there exists an unpaid balance under this Note.

      3. Interest only shall be payable monthly in arrears, commencing thirty
(30) days from the date hereof. Thereafter, on the first business day of each
month through and including the month in which the Due Date occurs, Borrower
shall pay monthly installments of interest only.

      4. Upon an "Event of Default," as defined in the Bridge Loan Agreement
described below, the rate of interest accruing on the amount of the entire
Commitment of this Note shall increase to fifteen percent (15%) per annum. Such
default interest rate shall continue until all defaults are cured.

      5. This Note is subject to the terms of a Bridge Loan and Control Share
Pledge and Security Agreement (the "Bridge Loan Agreement") of even date
herewith by and between the Borrower and the Lender. This Note is secured by
collateral pledged by the Borrower and the Subsidiaries of the Borrower to the
Lender pursuant to a Security Agreement of even date herewith by and among the
Borrower, the Subsidiaries and the Lender (the "Security Agreement"), as well as
by the deposit into escrow of the Borrower Control Shares (as defined in the
Bridge Loan Agreement) pursuant to the terms of a Pledge and Escrow Agreement of
even date herewith by and among the Borrower, the Lender and Gottbetter &
Partners LLP, as escrow agent (the "Escrow Agreement"). All capitalized and
undefined terms herein shall have the meaning given them in the Bridge Loan
Agreement, the Security Agreement or the Escrow Agreement.

<PAGE>

      6. Upon the occurrence of an Event of Default under the Bridge Loan
Agreement or the Security Agreement, the entire principal amount outstanding
hereunder and all accrued interest hereon, together with all other sums due
hereunder, shall, as provided in the Bridge Loan Agreement, after the expiration
of the applicable Cure Period become immediately due and payable. If such Event
of Default is cured within the Cure Period, including but not limited to by
payment in full of the entire principal amount outstanding hereunder and all
accrued interest hereon, together with all other sums due hereunder, and
provided that the Lender has received repayment in full of the Purchase Price of
the Borrower Control Shares, then all indebtedness evidenced hereby shall be
deemed canceled and paid in full, and the Security Agreement and the liens
created thereby shall be terminated and of no further force and effect.

      Notwithstanding the foregoing, if an Event of Default is cured prior to
the end of the Cure Period (including, but not limited to, an Event of Default
pursuant to Section 6.1(d) of the Bridge Loan Agreement), the Borrower shall use
its best efforts to ensure that the Merger and the Transactions are consummated.

      7. This Note is secured by and is entitled to the benefits of the Security
Agreement. In addition to the rights and remedies given it by this Note and the
Security Agreement, the Lender shall have all those rights and remedies allowed
by applicable laws, including without limitation, the Uniform Commercial Code as
in effect in the State of New York. The rights and remedies of the Lender are
cumulative and recourse to one or more right or remedy shall not constitute a
waiver of the others. The Borrower shall be liable for all commercially
reasonable costs, expenses and attorneys' fees incurred by the Lender in
connection with the collection of the indebtedness evidenced by the Note.

      8. To the extent permitted by applicable law, the Borrower waives all
rights and benefits of any statute of limitations, moratorium, reinstatement,
marshalling, forbearance, valuation, stay, extension, redemption, appraisement
and exemption now provided or which may hereafter by provided by law, both as to
itself and as to all of its properties, real and personal, against the
enforcement and collection of the indebtedness evidenced hereby.

      9. All notices, requests, demands, and other communications with respect
hereto shall be in writing and shall be delivered by hand, sent prepaid by a
nationally-recognized overnight courier service or sent by the United States or
Canadian mail, certified, postage prepaid, return receipt requested, at the
addresses designated in the Bridge Loan Agreement or such other address as the
parties may designate to each other in writing.

      10. This Note or any provision hereof may be waived, changed, modified or
discharged only by agreement in writing signed by the Borrower and the Lender.
The Borrower may not assign or transfer its obligation hereunder without the
prior written consent of the Lender.

      11. The term "the Borrower" shall include each person and entity now or
hereafter liable hereunder, whether as maker, successor, assignee or endorsee,
each of whom shall be jointly, severally and primarily liable for all of the
obligations set forth herein.

      12. If any provision of this Note shall for any reason be held invalid or
unenforceable, such invalidity or unenforceability shall not affect any other
provision of this Note, but this Note shall be construed as if this Note had
never contained the invalid or unenforceable provision.

      13. This Note shall be governed by and construed in accordance with the
domestic laws of the State of New York, without giving effect to any choice of
law provision or rule. Any controversy or dispute arising out of or relating to
this Note shall be settled solely and exclusively in accordance with the
provisions of the Bridge Loan Agreement and the Security Agreement, dated as of
even date herewith, which provisions are incorporated by reference herein as
though fully set forth.
<PAGE>

      IN WITNESS WHEREOF, the undersigned Borrower has caused the due execution
of this Bridge Loan Promissory Note as of the day and year first herein above
written.

                                        GRAN TIERRA ENERGY INC.

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

<PAGE>

                                   SCHEDULE A

         This schedule sets forth the principal amount borrowed by Borrower from
the Lender, up to the maximum amount set forth on the face of this Note.

--------------------------------------------------------------------------------
                                                   Signature of Authorized
Date                    Principal Amount             Officer of Borrower
--------------------------------------------------------------------------------
September 1, 2005        $6,655,198.30
--------------------------------------------------------------------------------
October 7, 2005               $800,000
--------------------------------------------------------------------------------
November 1, 2005              $700,000
--------------------------------------------------------------------------------

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