Two thoughts:
1) Netware over IP uses TCP port 396. Allow that port over the PIX.
2) Depending on your network, look into setting up a GRE tunnel between routers across the firewall, run IPX/IP over it, and set the PIX to allow GRE across it (eg access-list 101 permit gre host 11.11.11.11 host 10.10.10.10).
If traffic is getting blocked, look at your syslog or show log to see what is getting dropped and open the ports. You may also want to use a sniffer to verify what's really going on.
Hope it helps.
Steve