I think you are actually on the right track to do the debugger routine. As others have said, if you know where it's failing, start tracing from there.

I've been in similar circumstances and I use the GUI Debugger and had great success with it. You can expand or contract data structures which is nice and since you can see your code, you can decide where you want to set your breakpoints. Plus it runs great on win32 boxes too.

Hope that helps!

There is no emoticon for what I'm feeling now.