**Exhibit 10.68**ASSIGNMENT AGREEMENT (THE “**AGREEMENT**”) ENTERED INTO BY AND BETWEEN RIO VISTA OPERATINGPARTNERSHIP, L.P. (HEREINAFTER REFERRED TO AS THE “**ASSIGNOR**”), AND TRANSMONTAIGNE PARTNERSL.P. AND. TRANSMONTAIGNE PRODUCT SERVICES, INC. (HEREINAFTER REFERRED TO AS THE“**ASSIGNEES**”) PURSUANT TO THE FOLLOWING RECITALS, STATEMENTS AND CLAUSES:**R E C I T A L S**A. TLP and RVOP are parties to a Letter of Intent (the “**LOI**”) dated September 12. 2007pursuant to which TLP is paying RVOP a refundable deposit in the amount of Six Million FiveHundred Thousand Dollars ($6,500,000.00) (the “**Deposit**”) in connection with theproposed purchase of certain of RVOP’s assets.B. TPSI and RVOP are parties to that certain Restated and Amended Promissory Note (the“**Promissory Note**”) in the principal sum of One Million Dollars ($1,000,000.00), datedSeptember 12, 2007, pursuant to which RVOP has agreed to pay to TPSI the principal sumtogether with interest (the “**Loan**”) pursuant to the terms and conditions set forth inthe Promissory Note.C. The obligations of RVOP under the LOI to refund the Deposit and under the Promissory Note torepay the Loan (collectively, the “**Secured Obligations**”) are secured by a securityinterest in specified collateral as set forth in that certain Restated and Amended SecurityAgreement (as amended, restated, supplemented or otherwise modified from time to time, the“**Security Agreement**”), dated September 12, 2007, entered into by and among RVOP andthe Pledgees.D. Pursuant to the obligations assumed by RVOP under the RVOP Agreements, and as security forthe timely payment in full when due (whether at stated maturity, by acceleration or otherwise)of the Secured Obligations, (i) Pledgor shall execute and deliver this Agreement in order toassign, upon an event of default under the RVOP Agreements, certain rights and actions thatPledgor is entitled in connection to the equity interests issued by Tergas, S. de R.L. de C.V.(“**Tergas**”), and (ii) RVOP will cause certain other agreements (the “Other MexicanSecurity Documents”) to be executed and delivered granting a perfected first priority pledgesand security interests to Pledgees in and to one hundred percent of the corporate capital ofPenn Octane de Mexico, S. de R.L. de C.V. and in Penn Octane de Mexico, S. de R.L. de C.V.E. The LOI, the Promissory Note, the Security Agreement and the Other Mexican Security Documentsare referred to herein as the “**RVOP Agreements**”). Capitalized terms used herein andnot defined herein shall have the meaning assigned to such terms in the Security Agreement.
 
 

 
**S T A T E M E N T S**I. The Assignor, through its trust delegates, hereby declares that: a) It is a Delaware partnership organized under the laws of Delaware. b) It has all the necessary and sufficient authority to enter into this Agreementand to perform its obligations hereunder and has been authorized to enter into thisAgreement through all required internal resolutions. c) It has executed certain option purchase agreements to purchase all the equityinterests that represent all the capital of Tergas (“**Option Agreements**”). d) The partners of Tergas have granted irrevocable powers of attorney to theAssignor to freely vote the equity interests that represent all the capital of Tergas(“**Stock Powers**”). e) The Option Agreements and the Stock Powers allow the Assignor to assign ordelegate its rights and actions under the Option Agreements and the Stock Powers(“**Tergas Rights**”). f) Its representative is duly authorized to enter into this Agreement on behalf ofthe Trustee, which authority has not been limited, revoked or modified in any way. g) The entering into this Agreement and the performance of its obligationshereunder do not contravene or result in a breach of (i) its trust purpose or (ii) anyapplicable law or any agreement to which it is a party. h) This Agreement constitutes a legal, valid and binding obligation of theTrustee, enforceable against the Trustee in accordance with its terms.II. Each Assignee, through its legal representatives, hereby declares that: a) It is a company or limited partnership duly organized, validly existing and ingood standing under the laws of the United States of America. b) Its legal representative has the authority to obligate the Assignees in termsof this Agreement, and such authority has not been limited or revoked in any way. c) It has the power and authority to enter into this Agreement, it has obtainedthe requisite corporate, other third party and governmental authorizations andapprovals, and has made all filings necessary to, enter into this Agreement, to performits obligations hereunder. d) The entering into this Agreement and the performance of its obligationshereunder do not contravene or result in any breach of (i) its by-laws and articles orincorporation, (ii) any applicable law, rule, decree or authorization(including any license or concession) applicable to Assignees, or (iii) anyagreement of any nature whatsoever to which Assignees may be a party. e) This Agreement constitutes a legal, valid and binding obligation of Assignees,enforceable against Assignees in accordance with its terms.Based on the above, the Parties hereby state that they consent that this Agreement is governedby the aforementioned Recitals and Statements and by the following:
 
2

 
**C L A U S E S**FIRST. Assignment. Assignor, upon the occurrence of a default under any of the RVOPAgreements (an “**Event of Default**”), by means of this Agreement irrevocably assigns andtransfers to the Assignees the Tergas Rights until the Secured Obligations under the RVOPAgreements have been paid in satisfaction of the Assignees. The Assignor and the Assignees agree(i) that the Tergas Rights shall not be modified without the prior written consent of Assignees;and (ii) upon Assignees’ request and during the term of this Agreement, the Assignor shall carryout any necessary act to guarantee that the Tergas Rights would not be modified or affected.Assignor hereby agrees to grant an irrevocable power of attorney in favor of Assignees as theexclusive authorized party to exercise the Stock Powers upon an Event of Default. In addition,Assignor agrees that, upon an Event of the Default, all of its rights under such Stock Powers shallbe waived in favor of Assignees.The assignment of the Tergas Rights shall not constitute payment, release or novation of theobligations of RVOP under RVOP Agreements, unless such obligations are effectively being paid withthe proceeds of the sale of the Tergas Rights to a third party. The Assignees shall not assume anyobligations of the Assignor related to the Tergas Rights. Such obligations shall remain with theAssignor, who shall comply with such in its totality. The Assignor does not have or retain anyrights to challenge the assignment of the Tergas Rights.SECOND. Obligations. The Assignor, in addition to comply with any other obligations underthis Agreement or applicable law, shall:(a) Give notices to the applicable parties and comply with the applicable requirements andformalities in order to make effective such assignment of Tergas Rights, including notificationthrough Notary Public to Messrs. José Vicente Soriano García and Dennis Michael Sánchez, partnersof Tergas, of the assignment referred to herein.(b) Carry out all the necessary or convenient acts to maintain the Tergas Rights and the rights ofthe Assignees under this Agreement.(c) Unless otherwise provided in this Agreement, not sell, pledge, assign, transfer, sell, lien orin any other way convey the Tergas Rights, or accept a lien on the Tergas Rights by any personother than the Assignees.
 
3

 
THIRTH. Further Assurances. Parties hereto hereby agree to execute and deliver suchfurther documents and to take such further actions as may reasonably be required to effect thetransactions contemplated hereby.FOURTH. Notifications. All notices, claims, instructions, or other communications to begiven under this Agreement shall be given in writing and will be deemed duly given when (a)personally delivered, or (b) sent by courier to the address mentioned below or such other addressnotified in writing from time to time to the other Parties, same which will be effective two daysafter receipt.To Assignor:Rio Vista Operating Partnership, L.P.