I don't know grub4dos at all, but..
First memory: 3GB is limit with 32-bits. Run Knoppix with the 64-bits option (cheat code knoppix64) and all memory will be reported and used.
Then Knoppix: Are you sure this should work? I think the problem may be in your sequence of commands - what are you really telling the Knoppix bootloader here?
Clearly, the Knoppix boot is searching for a loadable image, and doesn't find any. There is a cheat code for this type of booting, from 6.4.4 cheat code list:
Code:
knoppix bootfrom=/dev/sda1/KNX.iso Access image, boot from ISO-Image.
I would have tried setting up an ordinary grub entry, like I give an example of here: http://www.knoppix.net/forum/threads...e-from-scratch
with the bootfrom option used in the kernel line.