SSRS: URL Encoding in Report Services

I am trying to deploy a report and I added the following to the Report Properties: System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a. I am getting the following error message: "Error 1 Error while loading code module: ‘System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’. Details: Could not load file or assembly 'System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. 0 0 " I am running SQL Server 2012, Report Builder 3.0 and SQL Server Visual Studio 2010. I have copied System.Web to several locations on my C:\ drive, but am still getting the deploy error. What is the correct folder System.Web.dll should reside?