OLE DB Driver sql 2008r2 to Oracle failing
Install the Oracle Instant client - both the 32 and 64 bit versions find orasql12.dll and register it with regsvr32 orasql12.dll and c:\windows\syswow64\regsvr32.exe orasql12.dll for the 32 bit version. and add the oracle bin directory the the path environment variable

Make sure that you can see the oracle driver in ODBC both 32bit and 64bit and under data providers in the management studio. Check allow "Allow Inprocess" in the driver properties or run EXEC master.dbo.sp_MSset_oledb_prop N'OraOLEDB.Oracle', N'AllowInProcess', 1