Ran into this error while deploying an application to production:

Configuration Error

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: Could not load file or assembly ‘Microsoft.ReportViewer.WebForms, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’ or one of its dependencies. The system cannot find the file specified.

A quick search found the issue. The server needs these three files:

Microsoft.ReportViewer.Common.dll
Microsoft.ReportViewer.WebForms.dll
Microsoft.ReportViewer.ProcessingObjectModel.dll

These get installed by ReportViewer.exe, which can be found here:

C:Program FilesMicrosoft Visual Studio 8SDKv2.0BootStrapperPackagesReportViewerReportViewer.exe

In my case I just FTP’s up my entire C:Program FilesMicrosoft Visual Studio 8SDKv2.0BootStrapperPackagesReportViewerfolder to the server and then I was able to run the EXE without problem.