If the Novell Netware shares on your GSNW Windows NT 4.0 server disappear when you restart, you probably have a Cisco router.
If you do a trace, you will see that your GSNW server sends a Find Name to servername broadcast to the NetWare server, but does not receive a response.
The Cisco router is interfering with the request to find the Netware server.
Set the router port for Spantree PortFast. See http://www.cisco.com.
If other GSNW servers have the same problem, your router hardware may have a problem. Try inserting a hub
between the GSNW server and the router. If the problem goes away, the router is malfunctioning.