Are you using the same version of ODP.NET on both Windows environments? Only ODP.NET 220.127.116.11.0 and above support connecting to TimesTen. Can you verify the version of ODP.NET installed on Windows 7 server.
Yes, i am using the same version 18.104.22.168.0 in both Win 2003 and in Win 7.
in Regedit i am seeing
in Win 7
in Win 2003
I believe the entries from regedit confirm that you have ODP.NET 11.2.1 on Windows 7 but ODP.NET 11.2.2 on Windows 2008. TimesTen support was introduced in 22.214.171.124.0 and later versions of ODP.NET, please can you upgrade to 11.2.2 on Windows 7 and try again.
Check your PATH to make sure you are picking up the correct ODP and OCI DLLs. You need to be using the OCI DLLs from the 11.2.2 instantclient that gets installed along with TimesTen. It may be that you are picking up a different version of the OCI library.