Who are you trying to contact? If you have a problem using Knoppix, you are best to read the documentation, if that fails there is the forum, mailing list, and IRC Chat room.

If you have a question regarding this website then you can contact the webmaster. If you are wanting to contact Knoppix's creator, Klaus Knopper, then use the contact form on his website, be warned, he gets a lot of email, so unless you really need to contact him the use other channels.