If I have the wrong filesystem type I get the same error:
# mkdir /cdrom
# modprobe iso9660
# mount -t iso9660 /dev/sr0 /cdrom
# umount /cdrom
# mount -t foo /dev/sr0 /cdrom
mount: mounting /dev/sr0 on /cdrom failed: No such device
As I have no IDE driver, I also see this:
# mknod /dev/hdb b 3 64
# mount -t iso9660 /dev/hdb /cdrom
mount: mounting /dev/hdb on /cdrom failed: No such device or address
But that's not the error you reported, so I've no idea what went wrong.
BTW, if the block device works but is not in ISO9660 format, I get the
'Invalid argument' error from busybox 'mount'.