And also ditch 'default' if you haven't done that. Generically 'default' is fine, but for ntfs and vfat you will want to 'customize' the delimiter list. Here is what your fstab should look like for a CDROM on a sys with 1 HD and no extra partitions mounting it under it's normal place:
/dev/hdb /mnt/cdrom iso9660 user,noauto,ro 0 0
or something similar to that. Can you mount with the 'mount' command instead of simply adding it to fstab?