Sick G5, won't keep anything down...

My two week old (refurb'd) G5 iMac (17" iSight) is having an issue.
Last night, I was ripping some CDs into iTunes when it started ejecting them without me doing anything. I'd insert the CD and after about 10 seconds the Superdrive would spit it back out.
Apple's support center and a Google search didn't help with any info.
I tried restarting and tried a DVD too. Nothing.

Any ideas?

TIA

You should have the restore discs that came with the iMac, restart the machine and hold the 'C' key down, that will boot the Apple Hardware test, select the 'extended' test. Try an 'archive n install' by booting into 'Open Firmware' this time by holding the 'Option' key down to eliminate system software, then you might wanna run take it for an optical drive replacement if those fail.