HttpFiddler is a free HTTP debugging proxy and essential for daily asp.net developers work. It works as a proxy and change this settings in IE7 to forward request to fiddler. IE7 does not forward calls made to url contains localhost.
Workaround: make the call to the machine name in IE7. Fix the port in the setting of the Web projekt to a dedicated like 1000. So the call is now http://name:10000/....
The ASP.NET development server does only accept requests to localhost (hardcoded). So add a rule to fiddler which change the name like:
this snippet must be placed in function: OnBeforeRequest