Matching filename error after upgrading to unity 3.3

Hey, i upgraded a unity project from 2.6 to 3.3. After fixing some shader related errors now inside the editor everything worked fine. But any kind of build i tried ( WebPlayer, Standalone) crashed right after the start with the message:

The class defined in script file named 'xy' does not match the file name!

Which is simply wrong. I checked a thousand times and tried every fix i found here, including

• reimport (file, folder and project)

• compiled in Mono (instead of VS)

• recreation of the file (delete, create, paste content)

The Editor log file also shows no errors while building...

I found this older post: http://answers.unity3d.com/questions/43155/problem-with-upgrading-project-to-untiy-3.html?sort=oldest

with more or less the same problem...

Does anyone have an idea?

Thanks in advance