When you browse WCF service file (with extension svc) in Visual Studio 2008/2010 or from Internet Information Services (IIS) Manager you might hit an http error 404.3. The error message is completely meaningless.
Luckily I managed to search David Waddleton’s blog to solve the issue.
The error is mainly caused by the .Net Framework 3.0 Features in Vista and .Net Framework 3.5.1 Features in Windows 7.
The following command in %Windows%Microsoft.NetFrameworkv3.0Windows Communication Foundation should be able to solve the 404.3 error.
Do feedback to me if it does not solve the problem.