All machines running Panther?
I'd just verify personal file sharing is on for all machines. Also see the Print and Fax tab in System Pref's- (icon is little Epson looking printer) and verify "share my printers" is checked on host computer.
I have an Epson Stylus 740 and it's working across a Tibook, a duallie G5, and a 266mhz Tangerine iMac.