Unable to umount /KNOPPIX

[Sgeo]

Is it supposed to say "unable to umount /KNOPPIX, trying /dev/cloop instead"?

[UnderScore]

I too have seen that message on reboot/shutdown but mostly on older PCs.
I believe that the knoppix developers try to make Knoppix work on a wide variety of PC hardware. Iam guessing that in your example the developers noticed a problem with unmounting and created a script that works around that problem. From what I undertand, the message is normal.
I hope this helps.
James