I'm trying to compile a project that has 4 classes (4x .cpp and 4x .h files) but when I add one more class to my project, the whole thing won't compile! I've double checked the names, tried other names, etc. But nothing works.

The compiler exits and tells me he can't find the following files:
> object_script.main
> main.Debug

I'm using Qt Creator 1.0 and Qt 4.5 on a Windows XP machine

Is there some kind of max classes restriction?