If you develop an application that uses ReportViewer for displyaing SSRS reports, it could happen that it works properlly on local machine but when you upload it to other computer it gives the error:

Could not load file or assembly 'Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

The solution is to download and install proper version of the ReportViewer from Microsoft site.

Note: It doesn't need a license; it is a redistributable

ReportView version 2008:

http://www.microsoft.com/en-us/download/details.aspx?id=6576

ReportView version 2010:

http://www.microsoft.com/en-us/download/details.aspx?id=6442