Appletalk on Netware

[System Admin <sysadmin@hwcomp.demon.co.uk>]

We are running a Netware 3.12 server with a 486 processor and 64MB RAM.
We have four Apple Macs atteched to the server using the Netware for 
Mac Appletlk software.

There is an intermittent problem that seems to arise if for any reason
the network is running slowly or the cabling connection is temporarily
broken (ie: at a hub or switch):-
	One or two of the Mac users will not be able to log in.
	The message they receive is :-
		"The alias VOL1 could not be opened because
		 the shared disc VOL1 could not be found on
		 the network."

In the past we have got round the problem by adding a new ID to the 
user list and deleting the old one.  If that fails we have to reboot
the server.  As we have about 80 PC users as well as the Macs this is 
NOT a satisfactory solution.

While I am familiar with PC & Netware I know practically nothing about
Macs & our Apple supplier knows little about Netware.

Below is the AUTOEXEC.NCF for the server :-
	file server name HWCB2
	ipx internal net 8531155
	load a:\aspitran
	load a:\aha1540 above16=y port=330
	register memory 1000000 3000000
	mount sys
	load EPRO int=5 port=210 frame=ethernet_802.2 name=e8022
	bind IPX to EPRO net=6 
 	load EPRO int=5 port=210 frame=ethernet_802.3 name=e8023
	bind IPX to EPRO [int=5 port=210 frame=ethernet_802.3 name=e8023] 
net=2 
	load appletlk net=600000 zone={"TPBas"}
	load EPRO port=210 frame=ethernet_snap name=esnap
	bind appletlk esnap net=150-152 zone={"TPBas"}
	load afp
	load atps
	mount all
	load pserver general

If anyone can offer a suggestion as to what is causing this I would be 
very grateful

Alison