First of all download
IDEFIX or similar software so your cd drive(s) are actual mounted or edit a cd drive mount list so it points to "uaescsi.device") and give it the UNIT number of your drive, (ie UNIT=1 slave on IDE0 or UNIT 2= Master IDE1, UNIT= 3 Slave on IDE1)
I assume your using a IDE burner so use the CDR_SCSI3_ATAPI driver in Makecd and the standard ATAPI driver for your reading device (if using burner set the above driver)
Any probs/questions just ask or join the MAKECD mailing list (if that still exists).