FOURTH AMENDMENT TO RENEWAL PROMISSORY NOTE

WHEREAS, the undersigned five corporate entities (each, a "Maker;” or collectively, “Makers”) are each co-makers of a certain Renewal Promissory Note (the “Note”) dated May 21, 2007, in the original stated amount of $5,579,847.00, in favor of Teton, Ltd., a Texas limited partnership (“Payee”);

WHEREAS, the Note was previously amended by Amendment to Renewal Promissory Note dated May 21, 2008 (the “First Amendment”); by Second Amendment to Renewal Promissory Note and Loan Modification Agreement dated March 3, 2009 (the “Second Amendment”); and by Third Amendment to Renewal Promissory Note dated May 21, 2009 (the “Third Amendment”);

WHEREAS, the following additional monies (the “Additional Funds”) have been or are being advanced to Makers by Payee and are now part of the loan evidenced by the Note (the “Loan”): (i) on April 29, 2009, $100,000.00 was advanced to Maker(s) for working capital, and (ii) on May 20, 2009, $250,000.00 was advanced to Maker(s) for working capital;

1. Amendment to Note to Add the Additional Funds. The Note is hereby amended to confirm that the Additional Funds have been added to the outstanding principal balance of the Loan and shall be repaid under the terms of the Note. Consequently, the total outstanding principal balance of the Note is now $5,777,303.00, of which (i) $4,857,303.00 is accruing interest at eight percent (8%) per annum from January 4, 2008, and (ii) $920,000.00 in additional funds (including amounts reflected in the Second Amendment and $350,000.00 in Additional Funds as described herein) have been advanced and are accruing interest at eight percent (8%) per annum from the date of each additional advance, to-wit: