Q: they are both connected via Ethernet to a router. and the one with the panther dvd in it has windows xp on it
A: This can't be done through XP, it might be possible through OSX, but you would need a firewire cord for that to work. You could rent an external DVD reader from somewhere if you only want to do this once, but you won't be able to do it with XP. I assume you want to put panther on the G3, but you only have a DVD of it and not CDs? My only suggestion other than buying or renting an external dvd reader is to find a friend with a Mac and get a firewire cord, put the other Mac into Disk mode, (start up holding the T key) and you should be able to read any DVD in that computer from the G3, good luck