The driver you should use for IDE internal devices depend on the kernel you are using:
- With a 2.6 one, you MUST use ide-cdrom
- with a 2.4 ide-scsi
If you are running RHEL 4, then you might have a 2.6.9 if I remember correctly (uname -r to be sure). So the thing that you have to do is deleting all entries like '/dev/hdd=ide-scsi' in your bootloader config files
For LILO, look in /etc/lilo.conf for a line like this
... and don't forget to re-run lilo when you have modified the file
For GRUB, just edit the /boot/grub/menu.lst (or something similar), and remove the /dev/hdd=ide-scsi each time you see it.