EXHIBIT 10.28d

            FOURTH AMENDMENT TO REAL ESTATE PURCHASE AGREEMENT


         THIS FOURTH AMENDMENT TO REAL ESTATE PURCHASE AGREEMENT (the
"Amendment") is made and entered into as of the 4th day of May, 2001, by and
between TROUT CREEK PROPERTIES, LLC ("Seller") and CRESCENT RESOURCES, LLC,
formerly known as Crescent Resources, Inc. ("Buyer").

                                    RECITALS

         A. Seller and Buyer entered into that certain Real Estate Purchase
Agreement (the "Agreement") dated November 29, 2000 and First Amendment dated
January 17, 2001, and Second Amendment dated March 28, 2001, and Third Amendment
dated April 30, 2001, wherein Buyer agreed to purchase from Seller and Seller
agreed to sell to Buyer certain real property located in Pasco County, Florida,
described therein (the "Premises") in accordance with the terms and conditions
of such Agreement.

         B.       Seller and Buyer  desire to extend the  Investigation  Period
and  extend  the  Closing  Date to provide more time for Seller to satisfy
Conditions Precedent described in the Agreement.

                                    AGREEMENT

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants contained herein, and for other good and valuable consideration,
Seller and Buyer do hereby agree as follows:

         1. Closing Date. Pursuant to Paragraph 6(a) of the Agreement, Buyer's
obligation to close is conditioned upon issuance of permits from Southwest
Florida Water Management District ("SWFWMD") and the Army Corps of Engineers
("ACOE"). Seller has obtained the SWFWMD permit and is awaiting issuance of the
ACOE permit or confirmation that ACOE will not claim jurisdiction. Accordingly,
the Closing Date described in Paragraph 7(a) of the Agreement is hereby extended
to the earlier of (i) June 1, 2001, or (ii) 7 days after issuance and delivery
to Buyer of the ACOE permit, or (iii) 7 days after delivery to Buyer of written
confirmation from ACOE that it will not assert jurisdiction.

         2. Closing Extension. Paragraphs 7(a) and 7(b) of the Agreement give
Buyer the right to extend the Closing Date. If Buyer elects to extend the
closing beyond the Closing Date established in Paragraph 1 of this Amendment,
then Buyer shall give Seller written notice and pay the Extension Fee of
$100,000 to Seller on or before the Closing Date established in Paragraph 1
above. In such event, the closing shall be extended to no later than September
30, 2001, and the Purchase Price shall be increased by $100,000 for each 30-days
of closing extension beyond the Closing Date established in Paragraph 1 above.
The Extension Fee shall be applied to such increased Purchase Price at closing.
Buyer shall provide at least five (5) days notice to Seller of the Extended
Closing Date which shall be no later than September 30, 2001.

         3.       Investigation  Period.  The  Investigation  Period described
in Paragraph 3 of the Agreement is hereby extended to expire at 5:00 PM local
time in Tampa,  Florida,  on the date which is two (2) days prior to the
Closing Date established in Paragraph 1 above.

         4.       Ratification  of  Agreement.  This Amendment shall control any
conflicting  provisions of the Agreement or prior amendments, which is hereby
ratified and confirmed by Buyer and Seller.

         5.       Counterparts.  This Amendment may be executed in two or more
counterparts,  each of which shall be taken to be an original.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment as
of the day and year first above written.

SELLER:                                              BUYER:

TROUT CREEK PROPERTIES, LLC                 CRESCENT RESOURCES, LLC

By: /s/ Brian P. Burns                      By:  /s/ Michael Wiggins
    -------------------------                    ------------------------
Name:  Brian P .Burns                       Name:  Michael Wiggins

Title: Chairman                             Title:  Vice President

Date:  4 May 2001                           Date:   May 4, 2001