System.Web.Routing.RequestContext exists in both

thanks again

I did that this is my CustomRoute.cs code

using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Routing; using System.Web.Compilation; using System.Web.UI; public class CustomRouteHandler : IRouteHandler { public CustomRouteHandler(string virtualPath) { this.VirtualPath = virtualPath; } public string VirtualPath { get; private set; } public IHttpHandler GetHttpHandler(RequestContext requestContext) { var page = BuildManager.CreateInstanceFromVirtualPath (VirtualPath, typeof(Page)) as IHttpHandler; return page; } }

when i run website this error occur for above class

Error2The type 'System.Web.Routing.RequestContext' exists in both 'c:\Program Files\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Web.dll' and 'c:\Windows\assembly\GAC_MSIL\System.Web.Routing\3.5.0.0__31bf3856ad364e35\System.Web.Routing.dll'D:\behtop project\behtop website\App_Code\CustomRoute.cs1940D:\behtop project\behtop website\

Error1The type 'System.Web.Routing.IRouteHandler' exists in both 'c:\Program Files\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Web.dll' and 'c:\Windows\assembly\GAC_MSIL\System.Web.Routing\3.5.0.0__31bf3856ad364e35\System.Web.Routing.dll'D:\behtop project\behtop website\App_Code\CustomRoute.cs1035D:\behtop project\behtop website\