If you are building an ASP.NET web application that's going to get thousands of hits per hour, the execution overhead of Linq queries is going to consume too much CPU and make your site slow. There's a runtime cost associated with each and every Linq Query you write.
Apparently, the reason I was recieving the Internal Server error message was that I had installed SQL Server 2008, after installing Visual Studio 2010, and because of this it corrupted the IIS Machine level configuration files ("If you install VS2010 and then install VS2008 and VS2008 SP1, the configuration files for ASP.NET in IIS only include about 1/2 of the correct .Net 4.0 configuration sections." read more here).