FOURTH AMENDED AND RESTATED REVOLVING LINE OF CREDIT NOTE

FOR VALUE RECEIVED, the undersigned (hereinafter called “ Maker ”) does hereby unconditionally promise to pay to the order of Wells Fargo Bank, National Association , a national banking association (“ Payee ”), at its office at 1445 Ross Avenue, 3rd Floor, MAC T5303-031, Dallas, Texas 75202, the principal sum of ONE HUNDRED MILLION AND NO/100 DOLLARS ($100,000,000.00), or such lesser amount as has been loaned or advanced by Payee to Maker hereunder or under the Loan Agreement, in lawful money of the United States of America, together with interest from the date hereof until maturity at the rates per annum provided below.

1.   Definitions .  For purposes of this Fourth Amended and Restated Revolving Line of Credit Note (this “ Note ”), unless the context otherwise requires, the following terms shall have the definitions assigned to such terms as follows and capitalized terms used herein but not defined herein shall have the meanings therefor specified in the Loan Agreement:

“ Business Day ” shall mean:

(i)   for all purposes (other than as covered by clause (ii) below) any day except Saturday, Sunday or a day which in the United States is a legal holiday or a day on which banking institutions are authorized or required by law or other government action to close; and

(ii)   with respect to all notices and determinations in connection with, and payments of principal and interest on, a LIBOR Balance, any day which is a Business Day described in clause (i) above and which is also a day for trading by and between banks in the interbank eurodollar market.

“ Consequential Loss ” shall mean, with respect to Maker’s payment, or conversion to a different Interest Option, of all or any portion of the then-outstanding principal amount of any LIBOR Balance on a day other than the last day of the LIBOR Interest Period related thereto, any loss, cost or expense incurred by Payee in redepositing such principal amount, including the sum of (i) the interest which, but for such payment, Payee would have earned in respect of such principal amount so paid for the remainder of LIBOR Interest Period applicable to such principal amount, reduced, if Payee is able to redeposit such principal amount so paid for the balance of such LIBOR Interest Period, by the interest earned by Payee as a result of so redepositing such principal amount, plus (ii) any expense or penalty incurred by Payee on redepositing such principal amount.

“ Contract Rate ” shall mean a rate of interest based upon the LIBOR Base Rate or WFB Base Rate in effect at any time pursuant to an Interest Notice.

“ Dollars ” and the sign “ $ ” shall mean lawful currency of the United States of America.

“ Eurocurrency Reserve Percentage ” shall mean, with respect to each LIBOR Interest Period, the maximum reserve percentage (expressed as a decimal) in effect on the first day of any LIBOR Interest Period, as prescribed by the Board of Governors of the Federal Reserve System (or any successor), for determining reserve requirements applicable to “eurocurrency liabilities” pursuant to Regulation D or any other then applicable regulation of the Board of Governors (or any successor) which prescribes reserve requirements applicable to “eurocurrency liabilities,” as presently defined in Regulation D, or any eurocurrency funding.

“ Event of Default ” shall mean an Event of Default as such term is defined in the Loan Agreement.

“ Excess Interest Amount ” shall mean, on any date, the amount by which (i) the amount of all interest which would have accrued prior to such date on the principal of this Note (had the applicable Contract Rate at all times been in effect without limitation by the Maximum Rate) exceeds (ii) the aggregate amount of interest actually received by Payee on this Note on or prior to such date.

“ Federal Funds Effective Rate ” means, for any day, the weighted average of the rates on overnight Federal funds transactions with members of the Federal Reserve System arranged by Federal funds brokers, as published on the immediately following Business Day by the Federal Reserve Bank of New York or, if such rate is not published for any Business Day, the average of the quotations for the day of the requested advance received by Payee from three Federal funds brokers of recognized standing selected by Payee.

“ Interest Notice ” shall mean the written notice given by Maker to Payee of the Interest Options selected hereunder.  Each Interest Notice shall specify the Interest Option selected, the amount of the unpaid principal balance of this Note to bear interest at the rate selected and, if the LIBOR Base Rate is specified, the length of the applicable LIBOR Interest Period.

“ Interest Option ” shall have the meaning assigned to such term in paragraph 7 hereof.

“ Interest Payment Date ” shall mean (i) in the case of any WFB Base Rate Balance, at the maturity of this Note, and (ii) in the case of any LIBOR Balance, the last day of the corresponding LIBOR Interest Period with respect to such LIBOR Balance and at the maturity of this Note.

“ LIBOR Balance ” shall mean any principal balance of this Note which, pursuant to an Interest Notice, bears interest at a rate based upon the LIBOR Base Rate for the LIBOR Interest Period specified in such Interest Notice.

“ LIBOR Base Rate ” shall mean, with respect to each LIBOR Interest Period, on any day thereof the quotient of (i) the LIBOR Rate with respect to such LIBOR Interest Period, divided  by (ii) the remainder of 1.0 minus the Eurocurrency Reserve Percentage in effect on such day.

“ LIBOR Interest Period ” shall mean, with respect to any LIBOR Balance, a period commencing: (i) on any date upon which, pursuant to an Interest Notice, the principal amount of such LIBOR Balance begins to accrue interest at the LIBOR Base Rate, or (ii) on the last day of the immediately preceding LIBOR Interest Period in the case of a rollover to a successive LIBOR Interest Period, and ending one month, two months or three months thereafter as Maker shall elect in accordance with the provisions hereof; provided, that: (A) any LIBOR Interest Period which would otherwise end on a day which is not a Business Day shall be extended to the next succeeding Business Day unless such Business Day falls in another calendar month, in which case such LIBOR Interest Period shall end on the next preceding Business Day; and (B) any LIBOR Interest Period which begins on the last Business Day of a calendar month (or on a day for which there is no numerically corresponding day in the calendar month at the end of such LIBOR Interest Period) shall, subject to clauses (C) below and (A) above, end on the last Business Day of a calendar month; and (C) any LIBOR Interest Period which would otherwise end after November 19, 2008 shall end on November 19, 2008.

“ LIBOR Rate ” shall mean, with respect to each LIBOR Interest Period, the rate of interest determined by Payee to be the arithmetic average (rounded upward, if necessary to the nearest 1/16th of 1%) of the per annum rates of interest at which Dollar deposits with a maturity equal to the proposed LIBOR Interest Period (and in an amount approximating the LIBOR Balance) would be offered to Payee by major banks in the interbank eurodollar market at approximately 8:00 a.m. (Dallas, Texas time) on the Business Day immediately preceding the first day of such LIBOR Interest Period.

“ Loan Agreement ” shall mean that certain Loan Agreement, dated as of September 23, 2004, by and among Maker, Payee and the subsidiaries and/or affiliates of Maker from time to time a party thereto, as guarantors, as amended, restated, supplemented and/or modified from time to time.

“ Maximum Rate ,” as used herein, shall mean, with respect to the holder hereof, the maximum non-usurious interest rate, if any, that at any time, or from time to time, may be contracted for, taken, reserved, charged, or received on the indebtedness evidenced by this Note under the laws which are presently in effect of the United States and the State of Texas applicable to such holder and such indebtedness or, to the extent permitted by law, under such applicable laws of the United States and the State of Texas which may hereafter be in effect and which allow a higher maximum non-usurious interest rate than applicable laws now allow.  To the extent that any of the optional interest rate ceilings provided in Chapter 303 of the Texas Finance Code, as amended from time to time (as amended, the “ Texas Finance Code ”), may be available for application to any loan(s) or extension(s) of credit under this Note for the purpose of determining the Maximum Rate hereunder pursuant to the Texas Finance Code, the applicable “monthly ceiling” (as such term is defined in Chapter 303 of the Texas Finance Code) from time to time in effect shall be used to the extent that it is so available, and if such “monthly ceiling” at any time is not so available then the applicable “weekly ceiling” (as such term is defined in Chapter 303 of the Texas Finance Code) from time to time in effect shall be used to the extent that it is so available.

“ Regulation D ” shall mean Regulation D of the Board of Governors of the Federal Reserve System from time to time in effect and shall include any successor or other regulation relating to reserve requirements applicable to member banks of the Federal Reserve System.

“ Total Commitment ” shall mean $100,000,000.00.

“ WFB ” shall mean Wells Fargo Bank, National Association, a national banking association, and its successors and assigns.

“ WFB Base Rate ” shall mean, on any date of determination, a variable rate of interest per annum equal to the higher of either (a) the WFB Prime Rate, or (b) the Federal Funds Effective Rate plus one-half of one percent (0.50%).

“ WFB Base Rate Balance ” shall mean that portion of the principal balance of this Note bearing interest at a rate based upon the WFB Base Rate.

“ WFB Prime Rate ” shall mean the rate of interest most recently announced within Payee at its principal office in San Francisco as its prime rate and is a base rate for calculating interest on certain loans.  The rate announced by Payee as its prime rate may or may not be the most favorable rate charged by Payee to its customers. Each change in the WFB Prime Rate shall become effective without prior notice to Maker automatically as of the opening of business on the date such change is announced within Payee.

2.   Manner of Borrowing; Advance Requests .  A request for an advance under this Note shall be made, or shall be deemed to be made, if Maker gives Payee notice of its intention to borrow, in which notice Maker shall specify (i) the aggregate principal amount of such advance and (ii) the requested date of such advance, which shall be a Business Day.  Any such request for an advance shall be accompanied by an Interest Notice and shall be made (i) no later than 11:00 a.m. Dallas, Texas time at least three (3) Business Days prior to the requested advance date if the principal balance of such advance, pursuant to such Interest Notice, is to bear interest at a rate based upon the LIBOR Base Rate and (ii) no later than 11:00 a.m. Dallas, Texas time or the requested advance date if the principal balance of such advance, pursuant to such Interest Notice, is to bear interest at a rate based upon the WFB Base Rate.  Notwithstanding anything herein to the contrary, Payee shall have the right to refuse to accept a request for an advance under this Note if at the date any such request is made or any such advance is to be made there exists a default or an Event of Default under this Note or the Loan Agreement.  As an accommodation to Maker, Payee may permit telephonic requests for loans and electronic transmittal of instructions, authorizations, agreements or reports to Payee by Maker.  Unless Maker specifically directs Payee in writing not to accept or act upon telephonic or electronic communications from Maker, Payee shall have no liability to Maker for any loss or damage suffered by Maker as a result of Payee’s honoring of any requests, execution of any instructions, authorizations or agreements or reliance on any reports communicated to Payee telephonically or electronically and purporting to have been sent to Payee by any individual from time to time designated by Maker as an authorized officer and Payee shall have no duty to verify the origin or authenticity of any such communication.

3.   Payments of Interest and Principal .  Interest on the unpaid principal balance of this Note shall be due and payable on each Interest Payment Date as it accrues.  The unpaid principal balance of this Note shall be due and payable in full on November 19, 2008.

4.   Rates of Interest .  The unpaid principal of the WFB Base Rate Balance shall bear interest at a rate per annum which shall from day to day be equal to the lesser of (i) the higher of either (a) the WFB Base Rate in effect from day to day, minus one percent (1.00%) or (b) three percent (3.0%) , or (ii) t