Error Configuring Reporting Services in Team Foundation Server 2010 post install

Question

We are configuring SQL Server Reporting Services on an existing installation of TFS 2010 RTM.

After configuring the Warehouse, Analysis Services and Reports tab in the TFS Administration Console, I get the following error: "Failed to add BUILTIN\Administrators account to the TfsWarehouseDataReader role on the Tfs_Warehouse relational database."

However, when I open SQL Server Management Studio and look at the users for the Tfs_Warehouse database, BUILTIN\Administrators does exist as a user and is in the TfsWarehouseDataReader Role.

An empty Tfs_Warehouse database is created but nothing else happens.

Please help.

Thanks,

Dave