Bugs/5.1.1CD
From Knoppix Documentation Wiki
There are two problems with option label dos for loading FreeDos balder.img. There is no memdisk file in /boot/isolinux folder and the isolinux.cfg sintax is wrong
The correct syntax is
LABEL dos
KERNEL /boot/isolinux/memdisk
APPEND initrd=/boot/isolinux/balder.img