Microsoft.Http.dll : The Official Microsoft ASP.NET Forums:
Re: Microsoft.Http.dll

Jul 20, 2010 12:23 PM | LINK

Those are part of the standard .NET Framework install. Can you not find them?

By default in VS2010, the target framework is the ".NET Framework 4 Client Profile" which does not include those DLLs. Change the target framework to the dropdown choice ".NET Framework 4".

Argh. Maybe the third time this happens I'll remember it.