Hi Tom,
As it turns out, the problem was a self inflicted wound. Our Apple guy also has ain image server running. He turned it on the other day. I noticed in the logs that the system would ask for an address first from the FOG server and then from the Apple image server immediately after that. It would then invariably die while trying to connect to the Apple server. I unplugged then network card on the apple box and stuff started working again.
Thanks for the help!
John