I believe the problem is that OS X can only see other Appletalk servers if they're running Appletalk over TCP/IP, which means servers running OS 9. I'm not sure if there's a preference under OS 9 somewhere that switches Appletalk between TCP/IP and whatever it usually runs under (localtalk? Ethernet? I'm not that well-versed in networking protocols), but if there is, you will probably have to make sure they're running Appletalk over TCP/IP. If your servers are running earlier versions of Mac OS, you might be out of luck.