Possible that automountd is hitting it for some reason. Kill automount and see if the messages stop. Then restart it - messages start up again? If yes to both of these, then
something is wrong with the cdrom drive (hardware or software)
The error is returned because there is no disk in either drive. It is normal and can be ignored. For example let say if you tried to removed the cdrom and floppy from from the fstab and check again the /var/log/messages you wont find the errors again. Its a sort of normal disc detection process