what is giving you the message? (or rather when?)
Atapi is the one of the standards supported by the IDE interface, and some controllers do not support the full set of commands which is why some RAID / add in IDE controllers do not support CD/DVD drives (IIRC they use a subset of commands some of which are not needed/used by hard drives).
My guess is you've possibly got a CD/DVD device connected to a controller that doesn't support them.