Trouble with apt-get update.

I just got a new motheboard and had to do a reinstall of Knoppix. The version that I am using is 3.7. When I then issue "apt-get update', I get many messages of the ilk:

Err http://ftp.de.debian.org unstable/non-US/non-free Packages
404 Not Found
Ign http://ftp.de.debian.org unstable/non-US/non-free Release

In fact, I get this sort of message for the unstable/non-US entries and testing/non-US. Also this happens for several mirrors nand not just ftp.de.debian.org.

I have been trying for about 24 hours. The seems to leave me unable to update or install anything. Can you tell me what I am doing wrong.

Thanks in Advance

The "unstable/non-US" and "testing/non-US" Debian repositories are now gone (evidently, changes to US law no longer requires that certain cryptographic software be only downloaded from overseas). You can delete them from /etc/apt/sources.list and then do another "apt-get update".

For more information, see this post and this post on the Kanotix board.