attaching gdb causes pthread_create hang [gdb6.3, long subject]

[Bogdan Slusarczyk <bodzio131 at op dot pl>]

Hi everyone, maybe you can help me.
There is following scenario:
1) I use gdb6.3, which was build on some linux, and I cannot change its 
version and cannot build gdb for every linux on the world (I mean I have 
to deliver built gdb to customers, regardless of which linux they have)
2) mentioned gdb will be used for debugging another delivered 
application (huge and complicated)

Problem is, that gdb on on some linux machines works fine, on others it 
causes that inside debugged application pthread_create hangs (from 
boost::thread).
But:
- with simple application which uses boost::thread (pthread_create) it 
works fine
- when I build the same gdb version on such specific linux, it works 
fine too!
- it's not specific for linux distribution, my quess is that some 
additional installed packages (or differences between them) can cause 
this problem

And my questions
-what can cause mentioned problems? different system libraries (which 
one)? what else?
-what kind of operations does gdb which could harm debugged application?

Thank in advance
Bogdan