Marc,

We just an identical situation, where the NT clients hung as a result of
losing their network connection.  The only difference was that they would
start up again and every time they lost the network connection more sessions
were left hung.  By morning, we had numerous sessions hung all for the same
client.

We changed the idletimeout parameter for server options to 30.  It was set
at 15 previously.  I just made that change last night and this is the first
morning we have not had a problem.

It might be worth a try for you.

Brenda