1) I haven't heard from you in weeks.
2) I've installed Linux on some of the most balled up machines in existence. I've never had one problem with a CDROM.
You do know that you can make "boot floppies" that will start just like the CDROM boot, and get the install to the point that the ATAPI CDROM driver is loaded and ready, after which the install goes as before?
When you start turning off hardware features in BIOS, you are already dead in the water. Turn on PIO/UDMA for the CDROM (don't use a pre-Colombian CDROM you fished out of an Inca-era ToughShed in the back yard next to the sacrificial pyramid), start over and do it right.