Error "Unhandled exception has occurred in your application…Could not load file or assembly 'Microsoft.ReportViewer…"

How do I resolve this error, ‘Unhandled exception has occurred in your application. If you click Continue, the application will ignore this error and attempt to continue. If you click Quit, the application will close immediately. Could not load file or assembly ‘Microsoft.ReportViewer.WinForms.Verson= Culture=neutral. PublicKeyToken…’?

This error typically indicates the winform (RocktonReportEngine.exe) is trying to reference an assembly (.DLL) that it cannot find.

Please check to ensure the machine has the required DLL files in the same folder that contains the RocktonReportEngine.exe (should be the GP folder).  The required DLL files are:


If either of these are missing, then that is what is throwing the exception error.  The DRM installer contains these files in the Resource folder.

If PdfSharp-WPF.dll is missing, then it can just be copied to the GP folder.

However if RocktonSoftware.dll is missing, it needs more attention than just a copy.  It has to be copied, registered, and some other things that the installer (DRMSetup.exe) will do for you automatically.


Re-run the DRM installer on the workstation/server getting the error.