Here is the solution given by Microsoft :
You should delete 1 extra (parasite) zone from HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\
with pseudo-graphic number, you’ll see it before zone number 0.
The pseudo-graphic number they speak of before zone number 0 looks like a miniature upper case "L".
The error stops after restarting the computer .
On a new computer we’ve added all the frameworks and so on ,but still got a message from Microsoft Visual Studio 2010 – “Unable to start debugging on the web server. The web server could not find the requested resource. Click Help for more information. “
In our project it was Web Application ( MVC ) using WCF .
We just upgraded to WINDOWS 7 and started working with IIS 7.5 .
So the message was not to evident. We’ve remembered that in IIS 6 in Windows XP it had a problem with .mvc extentions.
So we figured we are missing the MIME TYPES . We had .mvc extention configured , so we’ve checked what extentions are missing and found out it was .svc
In order to resolve this you need to run “\%windir%\Microsoft.NET\Framework\v3.0\Windows Communication Foundation\ServiceModelReg.exe -i”. It will create required .svc mapping.
check that you have the extentions needed in Handler Mappings of the default web site