IIS, by default, prohibits service of many file extensions, `.cs` is one.

So the request is being killed by <strike>IIS</strike> ASP.net before it hits the REST handlers.

This can be fixed fairly easily.

%SYSTEM%\Microsoft.NET\Framework\v2.0.50727\CONFIG\Web.Config

    ....
    <httpHandlers>
       <add path="*.cs" verb="*" type="System.Web.HttpForbiddenHandler" validate="True"/>
    ....

And of course this is just my supposition. I am not privy to the inner workings of the SO servers.

But I do have a bit of experience with how an [HttpWorkerRequest][1] behaves.

If anyone needs a better dev server than the one that comes with VS08 or VS10 you can get one [here][2]


  [1]: http://msdn.microsoft.com/en-us/library/system.web.httpworkerrequest.aspx
  [2]: http://cassinidev.codeplex.com/