Type or Namespace Not Found

[hufaunder]

I have a web project and a class library project. In the web project I
am trying to use some classes in the class library project.
Unfortunately, I can't compile it. The error is:

The type or namespace name MyNamespace.Test could not be found.

In my web project I did add a reference to my class library. Doing that
the dll of the class library was added to the Bin directory of my web
project. Also, in the code file of the web project (where I reference
the class library) I did add a using MyNamespace.Test. Intelisense even
marks the class referenced in MyNamespace.Test green. Also when I type
"using MyNamespace." intelisense give me a drop down that includes
"Test". So it does know the reference but somehow the compiler doesn't.
Any help is appreciated.

Thanks