First Time Connection From Windows 7 to SQL Server 2005 Fails

Hi Everyone,

I have an application that connects to a SQL Server 2005 Standard Edition server. Most of the machines are running on Windows XP and can connect to the database successfully. But recently, I added machines that are running on Windows 7. These new machines fail to connect to SQL Server. But if I ignore the errors and continue (within the same  application), subsequent connections are OK. 

This is my connection string for all clients (XP and Windows 7)

Server=192.168.1.253;Failover Partner=192.168.1.252;Integrated Security=SSPI;Database=<mydbname>

I hope someone can help me.

Thanks,

Noob