Hmmmm. That could be tricky. You might verify that the one working
workstation really is using the software on the server and not using a
locally stored copy. I believe when FHC set FS up to be networked it
automatically installed the software on each machine and only used the
server for install and data.
It might also be worth checking the virus scanners. Either they may be
getting in the way or you might have a virus. I'm seen a lot of strange
things that ended up going away once an infection was found and removed.