2.3 Install CD: Won't mount CD

[Dave]

Hi,

I'm trying to install YDL 2.3 on a dual 800 MHz (Quicksilver) G4. I insert
the install cd, press the "c" key, and I'm presented with the boot prompt. I
enter:

install-text video=ofonly

And after choosing my keyboard layout, it claims "The installer was unable
to mount the CD/DVD". I've tried entering things like:

install-text video=ofonly hdi=scsi-ide

But it still doesn't work. I've also tried pressing
control-command-option-F2 and entering:

echo 0 > /proc/sys/dev/cdrom/check_media

and it still doesn't work...

Any ideas?

Thanks so very much,

Dave