THIRD AMENDMENT TO THE RESTRUCTURING AGREEMENT

EXHIBIT 4.2

THIRD AMENDMENT TO THE RESTRUCTURING AGREEMENT

This Third Amendment (the “Third Amendment”) to the Restructuring Agreement is entered into as of this 25th day of March, 2008, by and among:

(a) Compañía de Inversiones de Energía S.A. (the “Company” or “CIESA”);

(b) Petrobras Energía S.A. and Petrobras Hispano Argentina S.A., each jointly and severally with the other (these parties jointly referred to herein as “PESA”);

(c) Enron Pipeline Company Argentina S.A. (“EPCA”);

(d) ABN AMRO BANK N.V., Sucursal Argentina, solely in its capacity as trustee of the MSA Trust (the “MSA Trustee”); and

(e) AEI (formerly known as Xxxxxxx Energy International) as assignee and holder of 100% of the Existing Debt Obligations of the Equity Option Consenting Creditors and, therefore, the Majority Consenting Creditor (the “Equity Option Consenting Creditor” and, together with the Company, PESA, EPCA, and the MSA Trustee are each a “Party” and collectively, the “Parties”).

RECITALS

(i) WHEREAS, the Parties and other Consenting Creditors entered into a Restructuring Agreement dated as of September 1^st, 2005, as amended by the Amendment and the Second Amendment (the “Restructuring Agreement”) to restructure all the unsecured financial debt of the Company. The consummation of the transactions contemplated in the Restructuring Agreement is subject to, among other conditions precedent, the authorization and approval of the ENARGAS which to this date is still pending;

(ii) WHEREAS, Section 9.3. (a) of the Restructuring Agreement provides that if the Consenting Creditors Consummation Date shall not have occurred prior to December 31, 2007 the Company or the Majority Consenting Creditors may terminate the Restructuring Agreement (the “Termination Right”);

(iii) WHEREAS the Parties are willing to continue with their efforts to obtain the Regulatory Approvals;

NOW, THEREFORE, in consideration of the premises and the mutual covenants and agreements set forth in the Restructuring Agreement and herein, the Parties hereto agree as follows:

1. Definitions and Interpretation.

In this Third Amendment, unless otherwise defined herein, capitalized words or terms which are defined in the Restructuring Agreement shall have the meaning ascribed to them in such agreements and, unless the context otherwise requires, every reference in this Third Amendment to Sections shall be references to Sections of the Restructuring Agreement, as the case may be.

2. Amendment to Section 9.3 (a) of the Restructuring Agreement.

Paragraph (a) of Section 9.3 is hereby amended and replaced ab initio by including the following language in italics (only for identification purposes for the ENARGAS) as if it had originally been written as follows:

“(a) the Consenting Creditors Consummation Date shall have not occurred prior to December 31, 2008.”

3. Continuing Effect; No Other Amendments.

Except as expressly amended hereby, all of the terms of the Restructuring Agreement shall remain in full force and effect. The amendment provided for herein is limited to the specific Section of the Restructuring Agreement specified herein and shall not constitute an amendment of any other provisions of the Restructuring Agreement or the Section. The amendments introduced to the Restructuring Agreement herein shall become effective as from the signing of this Amendment by the Parties hereto.

IN WITNESS WHEREOF, each of the Parties hereto has caused this Third Amendment to the Restructuring Agreement to be executed by its duly authorized officers as of the date first above written.

		COMPAÑÍA DE INVERSIONES DE ENERGIA S.A.
		By:		/s/ Xxxx Xxxxxxx
				Name: Xxxx Xxxxxxx
				Title: Attorney
				Date: March 25, 2008
		PETROBRAS ENERGÍA S.A.
		By:		/s/ Xxxx Xxxxxxx
				Name: Xxxx Xxxxxxx
				Title: Attorney
				Date: Xxxxx 00, 0000
		XXXXXXXXX XXXXXXX XXXXXXXXX S.A.
		By:		/s/ Nicolas Mordeglia
				Name: Nicolas Mordeglia
				Title: Attorney
				Date: March 25, 2008
		ENRON PIPELINE COMPANY ARGENTINA S.A.
		By:		/s/ Xxxxxxx Xxxx Xxxxxxxx
				Name: Xxxxxxx Xxxx Xxxxxxxx
				Title: Attorney
				Date: Xxxxx 00, 0000
		XXX AMRO BANK N.V., Sucursal Argentina
		as trustee of the MSA Trust
		By:		/s/ X. Xxxxxxxxx Ranvier
				Name: X. Xxxxxxxxx Ranvier
				Title: Attorney
				Date: Xxxxx 00, 0000
		XXX
		By:		/s/ Xxxxx Xxxxxxx
				Name: Xxxxx Xxxxxxx
				Title: Attorney
				Date: March 25, 2008