ASP.NET MVC2 New Project Fails To Build with 'The type or namespace name 'Controllers' does not exist in the namespace..."

Symptom:

You have just created a brand new MVC2 Web project and tried to compile and run without anything modified and you get the following error:

The type or namespace name 'Controllers' does not exist in the namespace

What Fixed For Me:

The Unit Test project does not have the reference to the Main project. Just go to the Reference folder of the Unit Test Project and make a reference to the Main project.