Is your mbd fitted with the IT8212 bios controller, which is common, I believe, where mbd RAID option is offered? The IT8212 is temperimental when more than one make of optical drive is involved. Install manuals warn you to be careful, which isn't in itself much help.
A solution suggested elsewhere is to separate the CD's, DVD's from the HDD's and run them from a non-raid IDE pci card. click here