Many (most!) OEM-provided drivers don't support Windows-shared printers, because they bypass the cups/OS X comm protocols. Look here for drivers that will work for shared printing:
http://www.linuxprinting.org/macosx/
Keep in mind - Gimp-Print drivers are already installed in Panther. You DON'T need ghostscript with Panther (you do for Jaguar). Don't get the source code - get the .dmg installers!
Hope this helps.