"The web services enumeration components are not available"

For who met with the error "The web services enumeration components are not available. You need to reinstall Visual Studio to add web references to your application", when working with Web Service or Windows Communication Foundation, you can type the following

devenv / resetskippkgs

on Visual Studio 2005/2008 command prompt
Now you can continue your work without being haunted error message.

Ok, may it helps