some G3 imacs do not have the hardware to read/write DVD's
check the firewireport (firewire connected to an other mac) by starting up the G3 in target disk mode

(in target disk mode you cqn use the dvdwriter of the connected computer)

setup a small network, transfer the data to an other computer to write DVD

Click to expand...

That may be true (never tested that theory) but I have a firewire DVD burner (BusLink case with LG Burner) that I use as a DVD reader. I have connected it to many different iMac G3s to install Tiger (350-500mhz models) and never had an issue with the iMac reading from the drive. Since he is only trying to get the iMac to see and read a disc, not burn, then I figure that something may be up with the port itself.