Hi, I am getting this error

"[DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or access denied."

when trying to get some data from SQL Server 2000 database.
SQL Server is installed on Windows Server 2003, and i am testing the application from WinXP sp2. Testing from other machines with same settings goes properly, only this one machine doesn't work.
Any ideas are appreciated.

Thx

You may receive this error message when the following conditions are true: • SQL Server 2005 or SQL Server 2000 is installed on a cluster.
• You are connecting to a SQL Server named instance by using TCP/IP sockets.
• IPSec policy is enabled on the client domain.
• IPSec policy is not enabled on the server domain.

check these links :
http://support.microsoft.com/kb/888228

http://forums.asp.net/t/1089665.aspx