Machine hangs(Beta7), only reset button works

Hi
 
I've been seeing a pretty strange problem lately with my server. 

The box completely freeze typically when it's done running the first part of
my backup script, resulting in no possibility to login on the console or by
SSH, the freeze even happens when I'm sitting in a terminal and working.

There is no indication in log files etc. about what's causing the problem
and it's not breaking into debugger  either :-(

The backup script is really simple, creating a .tgz file of a given
directory, mounting a windows share (mount_smbfs) and copying the file. The
script is run by cron six times (start at the same time) in six different
directories, this results in the box freezes after the tar processes
finishes.

Attached is the dmesg.boot and the latest top, don't know if it's any use
but it's seems rather strange that a lot of processes are in a STATE usf
(not sure what this means but I don't sees this when the box is running
normally)

The kernel is mostly a generic with the following modifications:

options         IPFIREWALL
options         IPFIREWALL_VERBOSE
options         IPFIREWALL_VERBOSE_LIMIT=400
options         IPDIVERT
options         IPSEC
options         IPSEC_ESP
options         IPSEC_DEBUG
device ath
device ath_hal
options         KDB
options         DDB          

bash-2.05b# uname -a
FreeBSD bart.motd.dk 5.3-BETA7 FreeBSD 5.3-BETA7 #6: Tue Oct 19 00:36:59
CEST 2004     root_at_bart.motd.dk:/usr/obj/usr/src/sys/GW  i386

Any more info needed please let me know.

Best regards

- Tom