Mis Routing IP Traffic After Applying SP1 to Windows 2003

OK here is a wierd one.

We have 2 nic cards in our server

inside 192.168.2.x
dmz 172.16.0.x

anyone coming in over the VPN via Cisco Pix Firewall has an IP Address of

192.168.3
192.168.4
192.168.5
192.168.6
.............

Remote users lose access to the server 192.168.2.211
Users can not ping the server nor from the server can you ping any of the
remote locations.

Reading the logs on the Cisco it server after a period of time now
redirects all remote traffic on the 192.168 card to the DMZ card. 172.16.0
network.

If we disable the dmz everything goes back to normal.

Put people outside the network can no longer access the service availble on
the server because the dmz has been disable...

If we re-enable the dmz... all is well for a couple of hours. and then the
senario starts all over again...


Any Clues here...


Thanks