[Asterisk-Users] asterisk 1.2.7.1 crashing my newly built system

[T.S]

Hello folx!
I just started to play with *. I first installed it this past weekend on my
Solaris 9 ultra 5 test box. Now I'm attempting to put it on a freshly built
Linux box a mere few hours old. I've installed asterisk 1.2.7.1,
libpri-1.2.2, zaptel 1.2.5 and the latest asterisk-sounds 1.2.1. 
This is running (or installed) on my Slackware 10.2 box running kernel
2.4.31.  I'm testing with a sip channel (since I have no digital boards),
with Xlite 1105x release. 

The problem I'm having is with the fresh demo install instances. I was
testing out accessing vm and switching back and forth between lines on the
xlite client, when I received this message:

Apr 19 22:17:00 WARNING[2806]: chan_sip.c:1210 retrans_pkt: Maximum retries
exceeded on transmission 5CF3AB26-3EBC-4E74-89EA-9386624B0601 at 192.168.2.10
for seqno 49491 (Critical Response)

Then immediately my machine became unresponsive and my ssh connection
dropped. I had to reboot it to get back again. I've looked in
/var/log/messages to see if I can see the cause, but nothing is there
related to asterisk. I don't have this happening at all with my Solaris 9
box, which has been running the same tar files since this past weekend. I
really haven't changed anything from the default except uncomment out the
xlite sip user in sip.conf.

Can anyone shed some light as to what could be the cause for the error? Then
the drop in network connection and freezing the machine?

Thanks!

Terrelle