If the data source is a SharePoint farm, then 1) Ensure that "ConfigureSharePoint.exe -EnabledSharePointProtection" has been ...

If the data source is a SharePoint farm, then 
1) Ensure that "ConfigureSharePoint.exe -EnabledSharePointProtection" has been run on the front-end web server with the current SharePoint farm administrator credentials. 
2)Ensure that the SharePoint VSS writer is running on the front-end web server.