Having trouble using Excel pivots with Team Foundation warehouse in beta 2? If you're getting this error:
Initiatialziation of the data source failed.
Check the database server or contact your database administrator. Make sure the external database is available, and then try the operation again. If you see this message again, create a new data source to connect to the database.
Then try this:
Regsvr32 C:\Program Files\Common Files\System\Ole DB\msolap90.dll