Exhibit 10.21

AMENDMENT NO. 1 TO LOAN AGREEMENT

     THIS AMENDMENT NO. 1 (“Amendment”) is made and entered into as of February
19, 2003, by and between ZAMBA CORPORATION and ENTRX CORPORATION and modifies
the Loan Agreement (“Loan”) dated November 4, 2002, between the parties. Except
as expressly set forth herein, the terms and conditions of the Loan shall
continue in full force and effect. All references to section numbers below refer
to the respective section numbers in the Loan. Capitalized terms shall bear the
meanings for such terms set forth in the Loan.

  1.   Section 3.1.4 is modified by adding the following to the end of the
Section: “Subject to Borrower’s receipt from Lender of $450,000 on or prior to
February 19, 2003, and $200,000 on or prior to March 15, 2003, representing the
entire remaining balance of the Second Advance, Lender shall be entitled to
convert the aggregate principal amount of the First Advance and the Second
Advance that have been provided to Borrower, as well as $6,888.89 of interest
that has accrued prior to this Amendment, into shares of NextNet Wireless, Inc.
(“NextNet”) Series A Preferred Stock held by Borrower (the “Shares”) at a per
share conversion price that is the lesser of $6.00 per share or such lower
initial per share price (on a common share equivalent basis, without giving
effect to differences in rights or to anti-dilution provisions or any other
purchase price adjustments set forth in the NextNet financing agreement) that
NextNet agrees to receive for any sale of other preferred stock in an amount
that is at least one million dollars ($1,000,000.00) before June 30, 2003. A
prior election by Lender to convert the Advances it provided and eligible
interest under this Agreement shall not affect its eligibility to receive the
benefit of conversion at a lower initial per share price from a subsequent
NextNet financing agreement if Lender would have otherwise been eligible
pursuant to this Agreement to obtain such lower initial per share price if it
had waited until the NextNet financing agreement was completed to exercise its
conversion rights. If Borrower does not receive the entire remaining balance of
the Second Advance by remittances from Lender to Borrower of the amounts of
$450,000 on or prior to February 19, 2003, and $200,000 on or prior to March 15,
2003, the remedies set forth above that have not already been effectuated
pursuant to provisions of this Amendment shall apply. Notwithstanding the above,
each party acknowledges that Lender’s receipt of the Shares, at any price, may
be subject to the rights of first refusal on the parts of NextNet and certain of
its investors as set forth in the Right of First Refusal Agreement.”     2.  
Section 3.1.5 is modified by inserting, at the end of the paragraph, the
following: “No interest shall accrue or become due during any period in which
there exists an Event of Default by Lender. Any interest not paid prior to the
date of this Amendment shall not be due if during such period there was an Event
of Default by Lender.”     3.   Section 3.1.3 is eliminated in its entirety and
Borrower hereby expressly waives the obligation of Lender to advance the Third
Advance, and Section 6.2 is eliminated in its entirety and Lender expressly
waives its rights to convert all outstanding Advances under the Note into shares
of Borrower’s common stock.     4.   Section 3.3 of the Loan is deleted and the
parties acknowledge that all of Borrower’s rights and Lender’s obligations
related to the Option set forth in the Loan are terminated upon execution of
this Amendment, including but not limited to any obligation of Borrower to
reserve a sufficient amount of Shares for exercise of the Option.     5.  
Section 4.12 is modified by deleting “1,083,333” from the sixth line and
replacing same with “583,333.”     6.   Section 6.1.1 is modified by adding,
prior to “The NextNet Conversion Rate” in the eighth line, the following:
“Subject to Borrower’s receipt from Lender of $450,000 on or prior to
February 19, 2003, and $200,000 on or prior to March 15, 2003, representing the
entire remaining balance of the Second Advance, . . .”     7.   Section 6.3.1 is
modified by deleting the third paragraph and replacing it with the following:
“Upon execution of this Amendment, the parties shall instruct the Collateral
Agent to return 250,000 shares of Series A Preferred Stock of NextNet from the
Collateral to Borrower. On July 1, 2003, the Collateral Agent shall return to
Borrower all shares of Collateral not previously issued or returned.”

     IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed and delivered the date and year first above written.

  ZAMBA CORPORATION,
a Delaware corporation
By /s/ Michael H. Carrel
Name: Michael H. Carrel
Title: Chief Financial Officer

ENTRX CORPORATION,
a Delaware corporation

  By /s/ Brian Niebur
Name: Brian Niebur
Title: Chief Financial Officer