SQL server and firewall client of ISA server incompatibility   

In some computers, just a few in thousands, appeared the following message 
when tried to login in SQL.

Connection failed: 
SQLState: ‘S1T00’
SQL Server Error: 0
[Microsoft][ODBC SQL Server Driver]Timeout expired

When I click OK appears the dialog to introduce again user and password. And 
I just click OK again, without change user/password values, and the 
application enters without more errors. 

I am using an ODBC string to connect to DB. 
This happened in computers with the firewall client of ISA server. Even when 
I stop the firewall client of ISA server service, the error appears.
When I run the "WinsockFix" tool to clean TCPIP configuration, the problem 
disappears but the firewall client of ISA server don’t work anymore. When I 
reinstall the firewall client of ISA server, the problems appears again. 

What could be? Someone have any suggestion?
Thanks,
Rui Oliveira

date: Tue, 18 Dec 2007 10:04:04 -0800   author:   Rui Oliveira