freebsd stable - Jun 2005 - i386/81215 - Any help on how to investigate a system freeze?

Hi!

A few weeks ago I submitted this PR and obviously, there was not enough
information provided to get some help.

The PR is http://www.freebsd.org/cgi/query-pr.cgi?pr=i386/81215

As I am getting more and more headaches using an ugly resolution I would
like to make another round of investigations in order to get more
accurate information.

I plan to reinstall the laptop in order to be able to try -CURRENT on it
too but meanwhile, is there something I can do?

I am experiencing a whole system freeze by using gtk-apps under X with
the xorg ati driver. But how can I get deeper in finding where the
system freeze?
Of course, I have no core dump, the network freeze too. I don't have
serial ports, only : usb, ethernet, infra-red and firewire.

If you know of any tips, or documentation I can use, please, please,
feel free to suggest : I am ready to test anything.

Thanks for reading.

Philippe.