Loomish said:
CD-RW, not CD-RX. I'm sorry
It says "Burning the disk failed because this type of CD is not supported. Error: 0x80020043. What am I doing?
Oh, okay, no problem.
Has it been written to already by another computer, or is this the first time? If so, you may need to use Disk Utility (in the Utilities folder) to erase the disc first.
Otherwise, it could just be a weird difference between your drive and that disc brand...and you might need to try a different brand. That's a strange thing, but I've heard of it happening once in a rare while....
EDIT: There's also the possibility mentioned above by
CanadaRAM, but as far as Apple History says, the iMac went straight from CD to CD-RW....