It is a Hyper-V environment with 32 bit Server 2008 installed on the SQL Server and the application server. They are on the same physical host. They can ping each other by name and they can connect to each others file system via UNC path. The ODBC connection uses the SQL Server driver. I simply put in the SQL cluster name and the database users name and password and when I click Finish and then Test Data Source, it tells me that the Tests Completed Succesfully. But if I try open the database in SSMS it can't find the SQL Server. I only experience this trying to connect to this clustered database. I can connect to other database servers from this machine just fine. I have also tried to connect to the cluster via SSMS from machines other than my application server and get the same error.