How to diagnose system freezes?

[Steve Parker]

Hi,

I'm running FC4 (with all updates) and I'm frequently experiencing total 
system freezes (i.e. my only option is to reset).  I highly suspect this 
has to do with a third-party kernel module (Contivity VPN client v3.3 
from Apani) as it seems to occur only when the VPN connection is active 
- even though the modules are always loaded.

With no errors/messages in any of the system logs following a freeze 
(crash, lockup, insert-your-favorite-word-here), how does one go about 
diagnosing a problem like this?  It seems to be a common problem for 
many people (at least on fedoraforum.org).  Anyone?  Help would be 
greatly appreciated.  Is it worth submitting a bug to bugzilla if the 
Contivity modules are suspected?

Thanks!
Steve