Gdb crashing or not attaching in Netbeans

["erupter at libero dot it" <erupter at libero dot it>]

Hello.
I've used GDB as a standalone debugger before, maybe with one amateur 
interface until recently I discovered Netbeans.
During development of a program suddenly debugging stopped working.
If I load a simple hello world, GDB works fine.
In the program I'm re-writing now (old program whose external libraries got 
changed) GDB doesn't want to work anymore.
Now Netbeans doesn't provide any info at all to help me debug this, so I'm 
asking here: how can I gather information on this kind of malfunction?

It *seems* that there is a problem with the source of a library.
Meaning that if I exclude the include (and the relevant code which is most of 
it) GDB works.
The moment I include that external source, it stops working.
Files are there though and compilation goes without problems.

I'm really in the dark here.

Best regards
Claudio