XP Static IP’s not connecting to server

We are running Novell 5.1 and have 2 computers that are static IP’s the rest are DHCP. The two IP’s are sequential, as xxx.56, and xxx.57. When both PC’s are booted at the same time, or the higher IP is booted first, the one with the lower IP willnot find Novell, you can do any IP stuff (ie. surf the net, ping, etc..)but the computer will not find Novell to login. I can ping the server Ip, and it finds it, but the login process will not work. When the lower IP is turned on first and loggedin first they both work fine.

Any ideas.

Thanks