If you have knoppix, saying I want to install version 3.1 is not enough to tell if this is a good distro to install or not. There were several versions of 3.1 produced, and each is defined by its release date. For instance, the most recent version is Knoppix 3.2 (06-06-03) released on June 6, 2003.
I have done the hard drive install on several machines now, and it keeps getting better over time. If you are using a version that outputs German for the hard drive install (knx-hdinstall) you are using a VERY old version, and I would highly recommend upgrading. The new version is in English, and seems very stable in my experience.
Also, you may want to consider joining the forum at
www.knoppix.net for information in resolving issues, obtaining information, etc. That group is very responsive, and well moderated. I have always gotten a recommendation, suggestions, or solution (sometimes all three

within 24 hours.
Regards,