Document:

Exhibit 10.12

                             GUARANTY BY CORPORATION

     This Guaranty, dated as of May 23, 2006, is made by Tradestar Services,
Inc., a Nevada corporation (the "Guarantor"), for the benefit of Wells Fargo
Bank, National Association (with its participants, successors and assigns, the
"Lender"), acting through its Wells Fargo Business Credit operating division.

     The Lender, Tradestar Construction Services, Inc., a New Mexico corporation
("Tradestar"), and Petroleum Engineers, Inc., a Louisiana corporation
("Petroleum Engineers", and together with Tradestar, the "Borrower"), are
parties to a Credit and Security Agreement of even date herewith (as the same
may be amended, supplemented or restated from time to time, the "Credit
Agreement") pursuant to which the Lender may make advances and extend other
financial accommodations to the Borrower.

     As a condition to extending such credit to the Borrower, the Lender has
required the execution and delivery of this Guaranty.

     ACCORDINGLY, the Guarantor, in consideration of the premises and other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, hereby agrees as follows:

     1. Definitions. All terms defined in the Credit Agreement that are not
otherwise defined herein shall have the meanings given them in the Credit
Agreement.

     2. Indebtedness Guaranteed. The Guarantor hereby absolutely and
unconditionally guarantees to the Lender the full and prompt payment when due,
whether at maturity or earlier by reason of acceleration or otherwise, of (i)
the Obligations and (ii) each and every other sum now or hereafter owing to the
Lender by the Borrower, including but not limited to, debts, liabilities and
obligations arising out of loans, credit transactions, financial accommodations,
discounts, purchases of property or other transactions with the Borrower or for
the Borrower's account or out of any other transaction or event, owed to the
Lender or owed to others by reason of participations granted to or interests
acquired or created for or sold to them by the Lender, in each case whether now
existing or hereafter arising, whether arising directly in a transaction or
event involving the Lender or acquired by the Lender from another by purchase or
assignment or as collateral security, whether owed by the Borrower as drawer,
maker, endorser, accommodation party, guarantor, principal, surety or as a
member of any partnership, syndicate, association or group or in any other
capacity, whether absolute or contingent, direct or indirect, primary or
secondary, sole, joint, several or joint and several, secured or unsecured, due
or not due, contractual, tortious or statutory, liquidated or unliquidated,
arising by agreement or imposed by law or otherwise (all of said sums being
hereinafter called the "Indebtedness").

     3. Guarantor's Representations and Warranties. The Guarantor represents and
warrants to the Lender that (i) the Guarantor is a corporation, duly organized
and existing in good standing and has full power and authority to make and
deliver this Guaranty; (ii) the execution, delivery and performance of this
Guaranty by the Guarantor have been duly authorized by all necessary action of
its directors and shareholders and do not and will not violate the provisions

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of, or constitute a default under, any presently applicable law or its
Constituent Documents or any agreement presently binding on it; (iii) this
Guaranty has been duly executed and delivered by the authorized Officers of the
Guarantor and constitutes its lawful, binding and legally enforceable
obligation; and (iv) the authorization, execution, delivery and performance of
this Guaranty do not require notification to, registration with, or consent or
approval by, any federal, state or local regulatory body or administrative
agency. The Guarantor represents and warrants to the Lender that the Guarantor
has a direct and substantial economic interest in the Borrower and expects to
derive substantial benefits therefrom and from any loans, credit transactions,
financial accommodations, discounts, purchases of property and other
transactions and events resulting in the creation of the Indebtedness guarantied
hereby, and that this Guaranty is given for a corporate purpose. The Guarantor
agrees to rely exclusively on the right to revoke this Guaranty prospectively as
to future transactions, in accordance with paragraph 4, if at any time, in the
opinion of the directors or officers, the benefits then being received by the
Guarantor in connection with this Guaranty are not sufficient to warrant the
continuance of this Guaranty as to the future Indebtedness of the Borrower.
Accordingly, so long as this Guaranty is not revoked prospectively in accordance
with paragraph 4, the Lender may rely conclusively on a continuing warranty,
hereby made, that the Guarantor continues to be benefited by this Guaranty and
the Lender shall have no duty to inquire into or confirm the receipt of any such
benefits, and this Guaranty shall be effective and enforceable by the Lender
without regard to the receipt, nature or value of any such benefits.

     4. Unconditional Nature. No act or thing need occur to establish the
Guarantor's liability hereunder, and no act or thing, except full payment and
discharge of all of the Indebtedness, shall in any way exonerate the Guarantor
hereunder or modify, reduce, limit or release the Guarantor's liability
hereunder. This is an absolute, unconditional and continuing guaranty of payment
of the Indebtedness and shall continue to be in force and be binding upon the
Guarantor, whether or not all of the Indebtedness is paid in full, until this
Guaranty is revoked prospectively as to future transactions, by written notice
actually received by the Lender, and such revocation shall not be effective as
to the amount of Indebtedness existing or committed for at the time of actual
receipt of such notice by the Lender, or as to any renewals, extensions,
refinancings or refundings thereof.

     5. Dissolution or Insolvency of Guarantor. The dissolution or adjudication
of bankruptcy of the Guarantor shall not revoke this Guaranty, except upon
actual receipt of written notice thereof by the Lender and only prospectively,
as to future transactions, as herein set forth. If the Guarantor shall be
dissolved or shall be or become insolvent (however defined), then the Lender
shall have the right to declare immediately due and payable, and the Guarantor
will forthwith pay to the Lender, the full amount of all of the Indebtedness
whether due and payable or unmatured. If the Guarantor voluntarily commences or
there is commenced involuntarily against the Guarantor a case under the United
States Bankruptcy Code, the full amount of all Indebtedness, whether due and
payable or unmatured, shall be immediately due and payable without demand or
notice thereof.

     6. Subrogation, etc. The Guarantor hereby waives all rights that the
Guarantor may now have or hereafter acquire, whether by subrogation,
contribution, reimbursement, recourse, exoneration, contract or otherwise, to
recover from the Borrower or from any property of the Borrower any sums paid
under this Guaranty. The Guarantor will not exercise or enforce any right of

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contribution to recover any such sums from any person who is a co-obligor with
the Borrower or a guarantor or surety of the Indebtedness or from any property
of any such person until all of the Indebtedness shall have been fully paid and
discharged.

     7. Enforcement Expenses. The Guarantor will pay or reimburse the Lender for
all costs, expenses and attorneys' fees paid or incurred by the Lender in
endeavoring to collect and enforce the Indebtedness and in enforcing this
Guaranty.

     8. Lender's Rights. The Lender shall not be obligated by reason of its
acceptance of this Guaranty to engage in any transactions with or for the
Borrower. Whether or not any existing relationship between the Guarantor and the
Borrower has been changed or ended and whether or not this Guaranty has been
revoked, the Lender may enter into transactions resulting in the creation or
continuance of the Indebtedness and may otherwise agree, consent to or suffer
the creation or continuance of any of the Indebtedness, without any consent or
approval by the Guarantor and without any prior or subsequent notice to the
Guarantor. The Guarantor's liability shall not be affected or impaired by any of
the following acts or things (which the Lender is expressly authorized to do,
omit or suffer from time to time, both before and after revocation of this
Guaranty, without consent or approval by or notice to the Guarantor): (i) any
acceptance of collateral security, guarantors, accommodation parties or sureties
for any or all of the Indebtedness; (ii) one or more extensions or renewals of
the Indebtedness (whether or not for longer than the original period) or any
modification of the interest rates, maturities, if any, or other contractual
terms applicable to any of the Indebtedness or any amendment or modification of
any of the terms or provisions of any loan agreement or other agreement under
which the Indebtedness or any part thereof arose; (iii) any waiver or indulgence
granted to the Borrower, any delay or lack of diligence in the enforcement of
the Indebtedness or any failure to institute proceedings, file a claim, give any
required notices or otherwise protect any of the Indebtedness; (iv) any full or
partial release of, compromise or settlement with, or agreement not to sue, the
Borrower or any guarantor or other person liable in respect of any of the
Indebtedness; (v) any release, surrender, cancellation or other discharge of any
evidence of the Indebtedness or the acceptance of any instrument in renewal or
substitution therefor; (vi) any failure to obtain collateral security (including
rights of setoff) for the Indebtedness, or to see to the proper or sufficient
creation and perfection thereof, or to establish the priority thereof, or to
preserve, protect, insure, care for, exercise or enforce any collateral
security; or any modification, alteration, substitution, exchange, surrender,
cancellation, termination, release or other change, impairment, limitation, loss
or discharge of any collateral security; (vii) any collection, sale, lease or
disposition of, or any other foreclosure or enforcement of or realization on,
any collateral security; (viii) any assignment, pledge or other transfer of any
of the Indebtedness or any evidence thereof; (ix) any manner, order or method of
application of any payments or credits upon the Indebtedness; and (x) any
election by the Lender under Section 1111(b) of the United States Bankruptcy
Code. The Guarantor waives any and all defenses and discharges available to a
surety, guarantor or accommodation co-obligor.

     9. Waivers by Guarantor. The Guarantor waives any and all defenses, claims,
setoffs and discharges of the Borrower, or any other obligor, pertaining to the
Indebtedness, except the defense of discharge by payment in full. Without
limiting the generality of the foregoing, the Guarantor will not assert, plead
or enforce against the Lender any defense of waiver, release, discharge or
disallowance in bankruptcy, statute of limitations, res judicata, statute of

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frauds, anti-deficiency statute, fraud, incapacity, minority, usury, illegality
or unenforceability which may be available to the Borrower or any other person
liable in respect of any of the Indebtedness, or any setoff available against
the Lender to the Borrower or any other such person, whether or not on account
of a related transaction. The Guarantor expressly agrees that the Guarantor
shall be and remain liable for any deficiency remaining after foreclosure of any
mortgage or security interest securing the Indebtedness, whether or not the
liability of the Borrower or any other obligor for such deficiency is discharged
pursuant to statute or judicial decision. The liability of the Guarantor shall
not be affected or impaired by any voluntary or involuntary liquidation,
dissolution, sale or other disposition of all or substantially all of the
assets, marshalling of assets and liabilities, receivership, insolvency,
bankruptcy, assignment for the benefit of creditors, reorganization,
arrangement, composition or readjustment of, or other similar event or
proceeding affecting, the Borrower or any of its assets. The Guarantor will not
assert, plead or enforce against the Lender any claim, defense or setoff
available to the Guarantor against the Borrower. The Guarantor waives
presentment, demand for payment, notice of dishonor or nonpayment and protest of
any instrument evidencing the Indebtedness. The Lender shall not be required
first to resort for payment of the Indebtedness to the Borrower or other
persons, or their properties, or first to enforce, realize upon or exhaust any
collateral security for the Indebtedness, before enforcing this Guaranty.
Guarantor waives the benefits of Arizona Revised Statutes Sections 12-1641,
12-1642, 33-814 and 12-1566.

     10. If Payments Set Aside, etc. If any payment applied by the Lender to the
Indebtedness is thereafter set aside, recovered, rescinded or required to be
returned for any reason (including, without limitation, the bankruptcy,
insolvency or reorganization of the Borrower or any other obligor), the
Indebtedness to which such payment was applied shall for the purpose of this
Guaranty be deemed to have continued in existence, notwithstanding such
application, and this Guaranty shall be enforceable as to such Indebtedness as
fully as if such application had never been made.

     11. Additional Obligation of Guarantor. The Guarantor's liability under
this Guaranty is in addition to and shall be cumulative with all other
liabilities of the Guarantor to the Lender as guarantor, surety, endorser,
accommodation co-obligor or otherwise of any of the Indebtedness or obligation
of the Borrower, without any limitation as to amount, unless the instrument or
agreement evidencing or creating such other liability specifically provides to
the contrary.

     12. Financial Information. The Guarantor will deliver to the Lender all
financial information concerning the Guarantor required to be delivered under
the Credit Agreement.

     13. No Duties Owed by Lender. The Guarantor acknowledges and agrees that
the Lender (i) has not made any representations or warranties with respect to,
(ii) does not assume any responsibility to the Guarantor for, and (iii) has no
duty to provide information to the Guarantor regarding, the enforceability of
any of the Indebtedness or the financial condition of the Borrower or any
guarantor. The Guarantor has independently determined the creditworthiness of
the Borrower and the enforceability of the Indebtedness and until the
Indebtedness is paid in full will independently and without reliance on the
Lender continue to make such determinations.

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     14. Miscellaneous. This Guaranty shall be effective upon delivery to the
Lender, without further act, condition or acceptance by the Lender, shall be
binding upon the Guarantor and the successors and assigns of the Guarantor and
shall inure to the benefit of the Lender and its participants, successors and
assigns. Any invalidity or unenforceability of any provision or application of
this Guaranty shall not affect other lawful provisions and application thereof,
and to this end the provisions of this Guaranty are declared to be severable.
This Guaranty may not be waived, modified, amended, terminated, released or
otherwise changed except by a writing signed by the Guarantor and the Lender.
This Guaranty shall be governed by and construed in accordance with the
substantive laws (other than conflict laws) of the State of Colorado. The
Guarantor hereby (i) consents to the personal jurisdiction of the state and
federal courts located in the State of Colorado in connection with any
controversy related to this Guaranty; (ii) waives any argument that venue in any
such forum is not convenient, (iii) agrees that any litigation initiated by the
Lender or the Guarantor in connection with this Guaranty may be venued in either
the state or federal courts located in the City and County of Denver, Colorado;
and (iv) agrees that a final judgment in any such suit, action or proceeding
shall be conclusive and may be enforced in other jurisdictions by suit on the
judgment or in any other manner provided by law.

     15. Waiver of Jury Trial. THE GUARANTOR HEREBY IRREVOCABLY WAIVES ALL
RIGHTS TO TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM ARISING OUT
OF, BASED ON OR PERTAINING TO THIS GUARANTY.

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<PAGE>

     IN WITNESS WHEREOF, this Guaranty has been duly executed by the Guarantor
the date first written above.

                                               TRADESTAR SERVICES, INC.

                                               By: /s/ Frederick A. Huttner
                                                   ------------------------
                                               Its: Secretary and Treasurer

                                               Address:
                                               3451 Candelaria, NE, Suite A
                                               Albuquerque, New Mexico  87107

STATE OF TEXAS    )
                  ) ss.
COUNTY OF HARRIS  )

     The foregoing instrument was acknowledged before me this 22nd day of May,
2006 by Frederick A. Huttner, the Secretary and Treasurer of Tradestar Services,
Inc., a Nevada corporation, on behalf of the corporation.

                                                 /s/ Kim M. Green
                                                 ----------------
                                                 Notary Public

                                      -6-Exhibit 10.13

                               FIRST AMENDMENT TO
                      AMENDED AND RESTATED CREDIT AGREEMENT

     THIS FIRST AMENDMENT TO AMENDED AND RESTATED CREDIT  AGREEMENT (this "First
Amendment")  is  entered  into  as of May  22,  2006  by  and  among  THE  CYMRI
CORPORATION,  a Texas corporation  ("CYMRI"),  TRIUMPH ENERGY, INC., a Louisiana
corporation  ("TEI") and  PETROLEUM  ENGINEERS,  INC.,  a Louisiana  corporation
("PEI")   (each  an  "Existing   Borrower"  and   collectively,   the  "Existing
Borrowers"),  STERLING  BANK,  a Texas  state  chartered  bank  ("Lender"),  and
TRADESTAR ACQUISITION SUB, L.L.C., a Nevada limited liability company ("Buyer").
Capitalized  terms used but not defined in this First Amendment have the meaning
given them in the Credit Agreement (defined below).

                                    RECITALS

     A. Existing Borrowers, PETROLEUM ENGINEERS INTERNATIONAL, INC., a Louisiana
corporation  ("PEII") and Lender entered into that certain  Amended and Restated
Credit  Agreement  dated  as of  December  3,  2004  (as  amended,  restated  or
supplemented, the "Credit Agreement").

     B. Effective as of May 19, 2006, PEII was merged with and into PEI with PEI
being the surviving corporation of the merger.

     C. Under the terms of that certain Agreement and Plan of Merger dated as of
May 23, 2006 (the "Merger Agreement") by and among Tradestar  Services,  Inc., a
Nevada corporation ("Tradestar"), Buyer, CYMRI, and Larry M. Wright, Franklin M.
Cantrell, Jr., Robert G. Wonish, and Michael W. Hopkins,  Tradestar will acquire
from CYMRI all the outstanding capital stock of PEI (the "Stock Sale") and CYMRI
will  merge with and into Buyer (the  "Merger"),  and  following  the Merger the
separate  corporate  existence of CYMRI shall cease, Buyer shall continue as the
surviving   corporation  (the  "Surviving   Corporation"  or  "New  CYMRI")  and
immediately after the Effective Time (defined below), the Surviving  Corporation
shall change its name to "CYMRI, L.L.C."

     D. The time that the Merger  becomes  effective  pursuant to Section 2.2 of
the Merger  Agreement is referred to in this First  Amendment as the  "Effective
Time." The date on which the  closing of the Stock Sale occurs is referred to in
this First Amendment as the "Stock Sale Closing Date".

     E. Lender is the current  beneficiary  of the liens and security  interests
granted by the  Existing  Borrowers to secure the  Obligations  under the Credit
Agreement.

     F. Tradestar and the Existing  Borrowers have requested that,  concurrently
with the  Stock  Sale and the  Merger,  Lender  release  certain  of its  liens,
security  interests and other rights  granted to it by CYMRI and PEI pursuant to
the Credit Agreement.

<PAGE>

          G.  Lender  has agreed to consent to the Stock Sale and the Merger and
     to amend the Credit  Agreement  to,  among other  things,  reflect  certain
     changes  resulting  from the Stock Sale and Merger and the Loan  Documents,
     subject to the terms and conditions of this First Amendment.

     NOW  THEREFORE,  for good  and  valuable  consideration,  the  receipt  and
sufficiency of which are acknowledged, the undersigned hereby agree as follows:

1.  Consent and Waiver. Existing Borrowers have requested that Lender consent to
the Stock Sale and to the Merger (the "Proposed  Transactions").  Subject to the
satisfaction  of the conditions set out in this First  Amendment,  Lender hereby
(a)  consents to the  Proposed  Transactions,  (b) waives any  violation  of, or
non-compliance  with, any provision of the Credit Agreement  resulting  directly
from the Merger or the Stock  Sale,  and (c) agrees not to  exercise  any of the
rights or remedies  available to it under the Loan Documents  which arise solely
as the result of the violation or  non-compliance  resulting  from the Merger or
the Stock Sale.  Except as set out in this  Section 1,  Existing  Borrowers  and
Buyer hereby agree that such waiver does not  constitute a waiver of any present
or future violation of or non-compliance with any provision of any Loan Document
or waiver of Lender's  right to insist upon  strict  compliance  with each term,
covenant, condition and provision of the Loan Documents.

2. Release of Liens and Release of PEI. Upon the  satisfaction of the conditions
set out in this First  Amendment,  (a) Lender shall release its liens on (i) the
capital  stock of PEI and (ii) the assets of PEI and (b) PEI shall cease to be a
Borrower under the Credit  Agreement and shall be released from its  obligations
as Borrowers under the Credit Agreement.

3. Joinder. As of the Effective Time, the Surviving Corporation (a) shall assume
all the  obligations of CYMRI,  as Borrower  under the Credit  Agreement and the
other Loan  Documents,  (b) agrees to be bound by the  provisions  of the Credit
Agreement or such other Loan Documents as if the Surviving  Corporation had been
an original party to the Credit Agreement or such other Loan Documents,  and (c)
confirms that,  after joining the Credit Agreement and the other Loan Documents,
the  representations  and warranties  set forth in the Credit  Agreement and the
other Loan  Documents  with respect to the Borrowers are true and correct in all
material respects as of the date of this First Amendment.

4. Amendments to Credit Agreement.  As of the Effective Time of the Merger,  the
Credit Agreement shall be amended as follows:

          (a) The  preamble to the Credit  Agreement  is deleted in its entirety
     and is replaced with the following:

                    "THIS  AMENDED AND  RESTATED  CREDIT  AGREEMENT  is made and
               entered into as of December 3, 2004, and amended  through May 22,
               2006,  by and among  CYMRI,  L.L.C.  a Nevada  limited  liability
               company,  formerly known as TRADESTAR  ACQUISITION SUB, L.L.C., a
               Nevada limited liability company  ("CYMRI"),  and TRIUMPH ENERGY,
               INC., a Louisiana  corporation  ("TEI")  (each  individually  and
               collectively,  the "Borrower"),  and STERLING BANK, a Texas state
               chartered bank (the "Lender")."

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<PAGE>

          (b) Section 1.2 of the Credit Agreement is hereby amended to delete in
     their  entirety  the defined  terms  Accounts  Receivable,  Borrowing  Base
     Accounts,   Eligible  Accounts  Receivable,   Lockbox,  Lockbox  Agreement,
     Stockholder Notes, and Stockholders.

          (c) Section 1.2 of the Credit Agreement is hereby amended to delete in
     their entirety the defined terms Borrowing Base Assets,  Change of Control,
     Collateral,  Compliance  Certificate,  CYMRI, Note and Permitted Liens, and
     replace  them  with  the  following   defined  terms  in  the   appropriate
     alphabetical order:

          "Borrowing  Base  Assets"  shall mean the  Borrowing  Base Oil and Gas
          Properties and the Certificates of Deposit.

          "Change of  Control"  shall mean an event or series of events by which
          (i) Tradestar ceases to own and control, directly and indirectly, 100%
          of the capital stock of CYMRI or (ii) CYMRI ceases to own and control,
          directly and indirectly, 100% of the capital stock of TEI.

          "Collateral" shall mean the Borrowing Base Oil and Gas Properties, the
          Certificates of Deposit and any other Property now or at any time used
          or intended as security for the payment or  performance  of all or any
          portion of the Obligations.

          "Compliance Certificate" shall mean each certificate, substantially in
          the form attached to the First Amendment as Exhibit III, executed by a
          Responsible  Officer of CYMRI and furnished to the Lender from time to
          time in accordance with Sections 5.2 and 5.3.

          "CYMRI" is defined in the  preamble  and shall mean CYMRI,  L.L.C.,  a
          Nevada  limited  liability   company,   formerly  known  as  Tradestar
          Acquisition Sub, L.L.C., a Nevada limited liability company.

          "Note" shall mean the replacement  promissory note of the Borrower, in
          the form  attached  as  Exhibit  I to the  First  Amendment,  with all
          renewals,  extensions for any period,  increases,  and  rearrangements
          thereof.

          "Permitted  Liens"  shall  mean (a) Liens for taxes,  assessments,  or
          other  governmental  charges  or  levies  not  yet  due or  which  (if
          foreclosure,  distraint,  sale, or other similar proceedings shall not
          have been  initiated) are being contested in good faith by appropriate
          proceedings,  and such  reserve as may be  required by GAAP shall have
          been made therefor, (b) Liens (including,  but not limited to, pledges
          or deposits) in connection  with workers'  compensation,  unemployment
          insurance  or other  social  security  (other  than  Liens  created by
          Section  4068  of  ERISA),   old-age  pension,   or  public  liability
          obligations which are not yet due or which are being contested in good
          faith by appropriate  proceedings,  if such reserve as may be required
          by GAAP shall have been made therefor,  (c) Liens in favor of vendors,
          carriers,  warehousemen,  repairmen,  mechanics, workmen, materialmen,

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<PAGE>

          construction,  or similar  Liens  arising by  operation  of law in the
          ordinary  course of business in respect of  obligations  which are not
          yet due or which  are being  contested  in good  faith by  appropriate
          proceedings,  if such  reserve as may be  required  by GAAP shall have
          been made therefor,  (d) Liens in favor of operators and non-operators
          under joint operating  agreements or similar contractual  arrangements
          arising in the  ordinary  course of the  business  of the  Borrower to
          secure  amounts  owing,  which  amounts  are not yet due or are  being
          contested in good faith by appropriate proceedings, if such reserve as
          may be required by GAAP shall have been made therefor, (e) Liens under
          production sales agreements,  division orders,  operating  agreements,
          and  other  agreements  customary  in the  oil and  gas  business  for
          processing,  producing,  and selling hydrocarbons securing obligations
          not  constituting  Indebtedness  and  provided  that such Liens do not
          secure obligations to deliver hydrocarbons at some future date without
          receiving  full  payment  therefor  within  90 days of  delivery,  (f)
          easements,   rights   of  way,   restrictions,   and   other   similar
          encumbrances,  and  minor  defects  in the  chain of title  which  are
          customarily  accepted in the oil and gas financing  industry,  none of
          which  interfere  with the  ordinary  conduct of the  business  of the
          Borrower or  materially  detract from the value or use of the Property
          to which they apply,  (g) Liens in favor of the Lender and other Liens
          expressly  permitted  under the Security  Instruments (h) second Liens
          (A) covering TEI's  Borrowing  Base Oil and Gas Properties  located in
          Louisiana  as  described  on Exhibit V  attached  hereto and (B) first
          Liens on the capital  stock of TEI in favor of the Prior  Stockholders
          but subject in each case to the  Subordination  Agreement  and (i) any
          other  Liens  approved  by  Lender  in its  sole  discretion  securing
          Indebtedness subordinated to the Obligations.

          (d) Section 1.2 of the Credit  Agreement is hereby  amended to add the
     following defined terms in the appropriate alphabetical order:

          "First  Amendment"  shall mean that certain First Amendment to Amended
          and Restated Credit Agreement dated as of May 22, 2006.

          "First Amendment Closing Date" shall mean May 23, 2006.

          "Prior  Stockholder Notes" shall mean the promissory notes executed in
          favor of the Prior  Stockholders in the original  aggregate  amount of
          $2,600,000  for which  Tradestar  has assumed (but for which CYMRI has
          not been release from) the obligations of the maker of such promissory
          notes.

          "Prior  Stockholders"  shall mean Don E. Claxton,  Betty Jane Claxton,
          C.F. Kimball, III, Linda R. Kimball, and The Irene and Alvin Bellaire,
          Jr. Trust.

          "Tradestar" shall mean Tradestar Services, Inc., a Nevada corporation.

          (e)  Section  2.2(a) of the  Credit  Agreement  is hereby  amended  by
     deleting  that Section in its entirety and  replacing it with the following
     text:

                                       4
<PAGE>

          "(a)  Proceeds  of  all  Loans  shall  be  used  solely  for  (i)  the
          acquisition and development of Oil and Gas Properties, (ii) payment of
          fees and expenses hereunder or (iii) for general corporate purposes."

          (f)  Section  2.7(a) of the  Credit  Agreement  is hereby  amended  by
     deleting  that Section in its entirety and  replacing it with the following
     text:

          "(a) The  Borrowing  Base as of the First  Amendment  Closing  Date is
          acknowledged by the Borrower and the Lender to be $6,500,000  which is
          attributable to the Borrowing Base Assets. The amount of the Borrowing
          Base (as adjusted from time to time under the terms of this Agreement)
          shall be reduced  by  $50,000 on the last day of each month  beginning
          June 30, 2006."

          (g)  Section  2.7(b) of the  Credit  Agreement  is hereby  amended  by
     deleting the last sentence of that Section in its entirety and replacing it
     with the following sentence:

          Notwithstanding  the  foregoing,  the  Lender  may at  its  discretion
          redetermine  the Borrowing  Base  attributable  to the Borrowing  Base
          Assets  and the  amount by which the  Borrowing  Base shall be reduced
          each  calendar  month as set forth in  Section  2.7(a) at any time and
          from time to time.  Lender may release the  Certificates of Deposit as
          Collateral at such time as it determines, in its sole discretion, that
          the Borrowing  Base Oil and Gas  Properties  are sufficient to support
          the  then-effective  Borrowing,  Base  taking into  consideration  all
          relevant factors.

          (h) Section  2.7(c) of the Credit  Agreement is hereby  deleted in its
     entirety and replaced with the following:

               "[Reserved]"

          (i)  Section  2.20 of the Credit  Agreement  is hereby  deleted in its
     entirety and replaced with the following:

               "2.20 [Reserved.]"

          (j) Section  3.1(q) of the Credit  Agreement is hereby  deleted in its
     entirety and replaced with the following:

          "(q) [Reserved.]"

          (k)  Section  5.5 of the  Credit  Agreement  is hereby  deleted in its
     entirety and replaced with the following:

          "5.5 Title Opinions; Title Defects.

          (a) Within 60 days  following  the First  Amendment  Closing  Date and
          promptly any time thereafter  upon the request of the Lender,  furnish
          to the Lender title  opinions,  in form and  substance  and by counsel
          satisfactory to the Lender, or other  confirmation of title acceptable

                                       5
<PAGE>

          to the Lender,  covering Oil and Gas Properties  constituting not less
          than  81%  of  the  value,  determined  by  the  Lender  in  its  sole
          discretion,  of the Borrowing Base Oil and Gas  Properties;  provided,
          however,  that within such 60-day period following the First Amendment
          Closing Date the Borrowing  Base Oil and Gas  Properties  owned by TEI
          shall be covered by current title opinions delivered to Lender in form
          and   substance   satisfactory   to  the  Lender  (and  not  by  other
          confirmation of title).

          (b)  Promptly,  but in any event  within 60 days  after  notice by the
          Lender,  clear or cure any defect in the title of the  Borrower to any
          of its Oil and Gas  Properties  if such defect,  in Lender's  opinion,
          materially  affects the value of the Oil and Gas  Properties.  If such
          title defects are not cured in a timely manner, Borrower shall pay all
          related  costs and fees  incurred  by the Lender to clear or cure such
          title defects."

          (l)  Section  5.26 of the Credit  Agreement  is hereby  deleted in its
     entirety and replaced with the following:

          "5.26 [Reserved.]"

          (m)  Section  5.27 of the Credit  Agreement  is hereby  deleted in its
     entirety and replaced with the following:

          "5.27 Within thirty (30) days after the First Amendment  Closing Date,
     obtain and  deliver to the Prior  Stockholders,  new or  replacement  Stock
     Certificates  which evidence CYMRI's stock ownership in TEI and are covered
     by the Stock Pledge  Agreement;  provided  that such  delivery of the Stock
     Certificates shall be subject to the Subordination Agreement."

          (n)  Section  8.16 of the Credit  Agreement  is hereby  deleted in its
     entirety and replaced with the following:

          "8.16  CYMRI as  Agent.  TEI  hereby  appoints  CYMRI as its agent and
     attorney-in-fact  to execute any certificates,  requests or other documents
     deliverable  under  this  Agreement  in the  name of  each  such  party  as
     Borrower,  and  Lender  shall be  authorized  to rely on any such  executed
     certificates,   requests  or  other   documents  as  acts  of  the  parties
     constituting   "Borrower"   without   the  need  of   further   inquiry  or
     investigation."

          (o) Exhibit VI attached to the Credit  Agreement is hereby  deleted in
     its entirety.

5.  Conditions.  This First  Amendment  shall be  effective  once the Stock Sale
Closing Date has  occurred,  the Effective  Time has  occurred,  and each of the
following have been delivered to Lender:

                                       6
<PAGE>

          (a) this First Amendment  executed by Existing  Borrowers,  Buyer, and
     Lender and dated as of the First Amendment Closing Date;

          (b) the Note executed by New CYMRI and TEI;

          (c) the Master  Amendment  to Deeds of Trust,  Mortgages  and Security
     Instruments executed by New CYMRI, TEI and Lender;

          (d) the Partial  Release of Amended and  Restated  Security  Agreement
     executed by Lender;

          (e) the Partial Release of Stock Pledge Agreement executed by Lender;

          (f) the  Ratification of Pledge of Certificates of Deposit executed by
     F.M. Cantrell, Jr. and Lender;

          (g) the opinion of Hirsch & Westheimer,  counsel to the  Borrower,  in
     form and substance acceptable to the Lender in its sole discretion;

          (h) UCC financing statements, amendments, releases and terminations in
     favor of Lender (as secured  party),  in form and  substance  acceptable to
     Lender, reflecting the changes effected by the Merger and the Stock Sale;

          (i)  evidence  satisfactory  to Lender that the Merger  Agreement  and
     Stock  Sale have been  consummated  and all  conditions  therein  have been
     satisfied, unless waived by Lender in writing;

          (j) a certificate issued by the secretary or an assistant secretary of
     CYMRI, New CYMRI and TEI certifying as to the incumbency of all officers of
     CYMRI,  New CYMRI and TEI who are  authorized to execute Loan  Documents on
     behalf  of such  CYMRI,  New  CYMRI and TEI,  respectively,  together  with
     specimen signatures of each such officer;

          (k)  copies  of the  Certificate  of  Formation  of New  CYMRI and the
     Certificate  of  Incorporation  of TEI and CYMRI  and,  in each  case,  all
     amendments thereto,  and copies of the bylaws and all amendments thereto of
     New  CYMRI,  TEI and  CYMRI,  accompanied  by a  certificate  issued by the
     secretary or an assistant secretary of New CYMRI, TEI and CYMRI, certifying
     to the effect that each such copy is correct and complete;

          (l)  copies of  corporate  resolutions  duly  adopted  by the board of
     directors  of CYMRI,  New CYMRI,  and TEI,  as  applicable,  approving  and
     authorizing  the Stock  Purchase  Agreement  and  Stock  Sale,  the  Merger
     Agreement  and the  Merger,  this  First  Amendment  and  the  transactions
     contemplated  herein, and the amendments to the other Loan Documents,  each
     accompanied by certificates  of the secretary or an assistant  secretary of
     CYMRI,  New CYMRI,  and TEI, as applicable,  to the effect that such copies
     are true and correct copies of resolutions  duly adopted at a meeting or by
     written  consent of the board of directors of CYMRI,  New CYMRI and TEI and
     that such resolutions  constitute all the resolutions  adopted with respect
     to such  transactions,  and that they have not been amended,  modified,  or
     revoked in any respect,  and are in full force and effect as of the date of
     such certificate;

                                       7
<PAGE>

          (m) certificates dated as of a recent date from the Secretary of State
     or other appropriate  Governmental  Authority  evidencing the existence and
     good standing of New CYMRI,  TEI and Tradestar in each entity's  respective
     jurisdiction of organization  and  certificates of authority to do business
     in any other jurisdictions where such entity does business;

          (n) results of searches of the UCC Records of the Texas  Secretary  of
     State from a source  acceptable  to Lender and  reflecting no Liens against
     any of the Collateral as to which  perfection of a Lien is  accomplished by
     the filing of a financing  statement  other than in favor of the Lender and
     Permitted Liens;

          (o) receipt of payment in  immediately  available  funds  necessary to
     reduce the  outstanding  Loans to an amount not to exceed  $6,500,000 as of
     the date hereof; and

          (p) such other documents as Lender may reasonably request.

6. Representations and Warranties. Buyer and TEI represent and warrant to Lender
that (a) they possess all requisite power and authority to execute,  deliver and
comply with the terms of this First Amendment, (b) this First Amendment has been
duly  authorized and approved by all requisite  corporate  action,  (c) no other
consent  of any  Person  (other  than the  Lender)  is  required  for this First
Amendment  to be  effective,  (d) the  execution  and  delivery  of  this  First
Amendment does not violate their organizational documents, and (e) no Default or
Event of  Default  has  occurred  and is  continuing.  The  representations  and
warranties made in this First Amendment shall survive the execution and delivery
of this First  Amendment.  No  investigation by Lender is required for Lender to
rely on the representations and warranties in this First Amendment.

7. Scope of Amendment and Release.  All references to the Credit Agreement shall
refer to the Credit  Agreement  as amended  by this First  Amendment.  Except as
affected  by this  First  Amendment  and the  amendments  to the Loan  Documents
executed  in  connection  with this  First  Amendment,  the Loan  Documents  are
unchanged  and continue in full force and effect.  However,  in the event of any
inconsistency  between  the terms of the Credit  Agreement  (as  amended by this
First Amendment) and any other Loan Document,  the terms of the Credit Agreement
shall control and such other  document  shall be deemed to be amended to conform
to the terms of the Credit Agreement.  Existing  Borrowers hereby release Lender
from any  liability  for  actions or  omissions  in  connection  with the Credit
Agreement  and the other Loan  Documents  prior to the First  Amendment  Closing
Date.

8. Miscellaneous.

          (a) Form. Each agreement,  document, instrument or other writing to be
     furnished to Lender in connection with this First Amendment must be in form
     and substance satisfactory to Lender and its counsel.

                                       8
<PAGE>

          (b) Headings.  The headings and captions used in this First  Amendment
     are for convenience only and will not be deemed to limit, amplify or modify
     the terms of this First Amendment,  the Credit Agreement, or the other Loan
     Documents.

          (c) Costs,  Expenses and Attorneys' Fees. Buyer and Existing Borrowers
     agree  to  pay or  reimburse  Lender  on  demand  for  all  its  reasonable
     out-of-pocket   costs  and  expenses   incurred  in  connection   with  the
     preparation, negotiation, and execution of this First Amendment, including,
     without  limitation,  the  reasonable  fees and  disbursements  of Lender's
     counsel.

          (d) Successors and Assigns. This First Amendment shall be binding upon
     and inure to the benefit of each of the  undersigned  and their  respective
     successors and permitted assigns.

          (f) Multiple Counterparts. This First Amendment may be executed in any
     number  of  counterparts  with the same  effect as if all  signatories  had
     signed the same document.  All counterparts  must be construed  together to
     constitute  one  and the  same  instrument.  This  First  Amendment  may be
     transmitted  and signed by facsimile or by portable  document format (PDF).
     The  effectiveness of any such documents and signatures shall have the same
     force and effect as  manually-signed  originals and shall be binding on the
     party  signing.  Lender  may  also  require  that any  such  documents  and
     signatures be confirmed by a  manually-signed  original;  provided that the
     failure to request or deliver the same shall not limit the effectiveness of
     any signature.

          (g) Governing  Law. This First  Amendment and the other Loan Documents
     must be construed, and their performance enforced, under Texas law.

          (h) Entirety.  THIS FIRST  AMENDMENT AND THE OTHER LOAN  DOCUMENTS (AS
     AMENDED  HEREBY)  REPRESENT  THE  FINAL  AGREEMENT  BY AND  AMONG  EXISTING
     BORROWERS, BUYER, NEW CYMRI, TEI AND THE LENDER AND MAY NOT BE CONTRADICTED
     BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS BY THE
     PARTIES. THERE ARE NO UNWRITTEN ORAL AGREEMENTS AMONG THE PARTIES.

                   [Signatures appear on the following pages.]

                                       9
<PAGE>

     This First  Amendment is executed as of the date set out in the preamble to
this First Amendment.

                                  THE CYMRI CORPORATION

                                  By:/s/ Larry M. Wright
                                     --------------------------------
                                         Larry M. Wright
                                         Chief Executive Officer

                                  TRIUMPH ENERGY, INC.

                                  By: /s/ Larry M. Wright
                                     --------------------------------
                                          Larry M. Wright
                                          Chief Executive Officer

                                  TRADESTAR ACQUISITION SUB, L.L.C.
                                  (to be known as CYMRI, L.L.C. immediately
                                  following the merger)

                                  By: /s/ Frederick A. Huttner
                                     -----------------------------------------
                                          Frederick A. Huttner
                                          Vice President

                                  PETROLEUM ENGINEERS, INC.

                                  By: /s/ Larry M. Wright
                                     --------------------------------
                                          Larry M. Wright
                                          Chief Executive Officer

                                  LENDER:
                                  -------

                                  STERLING BANK

                                  By: /s/ Jeff A. Forbis
                                     -----------------------------------------
                                          Jeff A. Forbis
                                          Senior Vice President

                                       10

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