481 is a pretty old client to begin with, have you tried any & all of the
following?
make sure DS is clean & healthy
make sure you are using the latest nwclient & patches
http://support.novell.com/filefinder
http://download.novell.com
make sure you have the server updated to the latest patches & oplocks level1
& 2 are set correct
SLP is setup properly on the server, & distributed properly to workstations
via dhcp (yes, you do want to set this up)
Internal DNS setup properly (yes, you do want to set this up)
that speed/duplex on *everything* is hardset, & hardset correctly
latest drivers for everything (nic/chipset/controller/etc)
check cables, make sure everything is cat5e certified, not using flat
cables/cat3/etc (ive seen it in a lot of places)
purge all volumes & turn off compression
make sure there is more than 10% free on EVERY volume
make sure bios/firmware to everything (server/raid
cards/switches/workstations/etc) up to date
run through
http://www.ithowto.com/novell/clientspeed.htm