Xcode 4 cannot debug certain files

I've a project with 2 targets just a normal target and a test target.
My test run fine but I cannot debug code used by my test code.

So if I put a breakpoint inside my testfiles, my debugger stops at these breakpoints but if I put a breakpoint inside my code that needs to be tested, it doesn't stop.

I've already putted a NSLog to make sure the line gets hit and I've put a breakpoint on the same line.
The NSLog gets executed but it never stops at my breakpoint.

Things I've tried:
- Creating a new project with the files copied to the new project
- Creating a new project and created new files and copied the original source code into these files
- Uninstalled Xcode and installed Xcode 4.1 for Snow Leopard.

Note: Yesterday everything seemed to work, but my Xcode crashed (again!) while working on the project. I only seem to have the problem since yesterday's crash. I thought the project file was corrupted but I've already created a new project so....