for some reason xp pro does not do netowrking automatically (not sure why, home seems to do it just fine), but it can be done.
The easiest way (if you don't mind having the classic login, is under my network connections go to view netword connections right click local network and find the item in the list with NW starting it, this is netware. double click it and install the client side (on both computers).
You may need your windows disc for this.
This should solve your problem, if not check to see that your firewall is not blocking these connections, as well you may want to run the network wizard and be sure that file/printer sharing is turned on.