PowerPivot and Excel Services

While working with getting PowerPivot and Excel Services working, I ran into this very annoying error:

ServerSession.ProcessServerSessionException: An exception during ExecuteWebMethod has occurred for server: http://servername:32843/811dd9f4d4ae48779f1dc7a03ba5d555/ExcelService*.asmx, method: GetHealthScore, ex: Microsoft.Office.Excel.Server.CalculationServer.Proxy.ServerSessionException: An error has occurred. —> System.ServiceModel.FaultException`1[System.ServiceModel.ExceptionDetail]: The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040) (Fault Detail is equal to An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is: System.IO.FileLoadException: The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)    at System.Reflection…    

Nothing in the event log…only this error with no reference to the assembly name or anything…annoying.  I found this nice post about debugging these type of errors:

http://blogs.msdn.com/b/suzcook/archive/2003/05/29/57120.aspx

You must download the SDK to get the tool:

http://www.microsoft.com/downloads/details.aspx?familyid=6B6C21D2-2006-4AFA-9702-529FA782D63B&displaylang=en

After installing, I wasn't seeing any binding errors.  In the documentation, you're suppose to restart the services that are using .NET after setting the logging.  I rebooted the server and the error didn't return…weird.

Chris