Thanks for the help. In response to all the questions:
1) The share is a Samba share and I am told that the folder is wide open on security - everyone can read/write, etc.
2) It does not happen every time a file is saved but it does happen 1-4 times a day during normal business hours (7:00AM to 5PM EST).
3) We are using Southware Revision 13. It was updated in January and the problems seem to have started at about the same time. We are told that revision 13 has a major *known* memory leak.
4) We finally broke down and contacted Microsoft and after two weeks of sending memory dumps, log files, etc - they can find no answer. THey told us that they can't identify any source of failure with Windows.
5) Southware apparently told my boss that they do not know how to correct the issue with the Southware software at this time nor could they offer any suggestion other than bringing Windows up to 8 GB RAM.
We followed the 8GB of RAM suggestion (although I did not see how that was supposed to make a difference) and also added a second terminal services server (the choice to do this also lost on me as TS can handle 80 users on 1GB RAM as long as there is adequate hard drive space for VM).
So now we have split up users between 2 servers both running Windows Enterprise 2003 SP2. One machine has 6GB and one machine has 8GB. The 8GB machine has not failed since loading it up. The 6GB machine is the one that continues to crash/reboot.
One point to consider. In troubleshooting this issue, we have taken many steps to resolve and in the course of that time have ended up replacing this server with more than 5 brand new servers. This pretty much rules out hardware since the same issue keeps happening on completely different hardware with clean installs of Windows each time. In the end, the only constant is the Linux Centos server and Southware, and the Accuthin Thin Client that runs on Windows.
Also, there does not seem to be a correlation between this issue and any specific user - but since we are here asking for help, maybe we haven't looked in the right place?
Final note: I have been asked to remove the MS Office suite, reboot, reinstall because we want to make sure that it is not Excel causing this. I have of course explained that this has been going on since the first server and has continued through the 6th server. Thanks for you help!