Problems with System.Web.Extensions dll

I'm moving an existing (working) site over from Webhost4Life, and got this error:

Server Error in '/' Application.
Could not load file or assembly 'System.Web.Extensions, Version=3.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

I've seen this before, and it's apparent by searching on google, that it's a very common error. Most advice I've seen says to change the reference to "System.Web.Extensions " to "Copy Local = true", and then upload the System.Web.Extensions dll to the "bin" directory. I even contacted Discountasp.net support, and they said to do the exact same thing. So, I uploaded it, and now, I get this error:

Server Error in '/' Application.
Could not load file or assembly 'System.Web.Extensions, Version=3.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Can anybody help me with this? Discountasp.net support suggested that the file might have been corrupted when I uploaded it - so they suggested using a different FTP program to upload it. I was using SmartFTP, and they suggested FileZilla. So, I tried that as well - but am still encountering the same error. I'm a bit intrigued by the reference to version "3.6.0.0" since everything I've seen suggests that the dll file is 3.5.0.0.

Any help would be much appreciated.

 

Hi Bruce, thanks for your reply. Yes, I did upload the system.web.extension.dll to my bin directory, however I now get the second error message that I posted above. I did finally get past this error last night though, and found that this line in the web.config file was causing the problem:

<add name="UrlRoutingModule" type="System.Web.Mvc.UrlRoutingModule, System.Web.Extensions, Version=3.6.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

This was under the <system.webServer><modules> section, and when I removed it, the error went away.

Now I'm faced with another problem... I'm using the WebFormsRouting tool that Phil Haack built (see: http://haacked.com/archive/2008/03/11/using-routing-with-webforms.aspx) - and it just does not work. I've looked at the logs and can see that the routes are being set, but it just displays a 404 error because it's looking for actual pages and now routes.