You might try ftp://ftp.knoppix.nl/pub/os/Linux/distr/knoppix/

If that's not satisfactory, then choose from
http://www.knopper.net/knoppix-mirrors/index-en.html

I have used my LiveCD to successfully reformat a broken USB with gparted,
on the Preferences menu.

Make sure your USB is large enough to hold the DVD version.

And, good luck.