title: Method 'get_EnableCdn' in type 'System.Web.UI.ScriptManager' from assembly 'System.Web.Extensions' does not have an implementation
body: <p>Can anyone explain a parse error like this one:</p>
  
  <blockquote>
    <p>"Method 'get_EnableCdn' in type 'System.Web.UI.ScriptManager' from assembly 'System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' does not have an implementation." </p>
  </blockquote>
  
  <p>My dev box runs Windows 7, framework 4.0 and latest Ajax tool kit. Site works locally as well as on test server (win 2003, framework 4.0 and latest Ajax tool kit), but on the production server (again Win 2003) the story is different. </p>
  
  <p>Ironically, the site on production server has been upgraded to framework 4.0 several months ago and works fine until I try to push updates by copying a published site. That's when I get this error.</p>
  
  <p>I also get this error if a just copy the working copy of the site into a new directory a create a new virtual directory.</p>
  
  <p>Reinstalled VS2010 but that didn't help. </p>
  
  <p>Anyway, a lot of the post with this error message are about users upgrading to 4.0 and receiving this error, which is not my case, so I'm at loss with this and would appreciate your input.</p>
  
  <p>Thanks,</p>