I wrote an application that uses PyQt4 to access a sqlite DB and I convertred  it using py2exe.

The python version is stable (I mean that I can't get it crash).
The binary version isn't, I mean that has an unpredictable behaviour:
- some times it works just fine
- some times it crashes easily but often in a way that I can't reproduce

My guess is that the problem could be on the GUI part (even if it happens quite often during db accesses, but my program access the db all the time).

How can I try to solve this problem?
How could I debug it?
I'd like not to go through the python interpreter's C code but only my script's python code.  Any way to do this??
Do exist any complex application (GUI+DB+network+...) that works converted with py2exe?
Are there any tips to let it happen?

My development configuration is
Python 2.5
Qt4      4.2.2
PyQt    4.1.1

I'll wait for answers!!!

Thanks in advance.