knoppix-installer will format the partition before installing everything...so it's formatting over the reiserfs format you're doing. You need to tell the installer script to use reiserfs, which you do by editing the .knofig file. You'll see what to change when you open the file. The easiest way is to configure all the stuff you can through the installer then choose to exit the installer and say yes when it asks if you want to save the configuration. Then I believe the .knofig file is in the /root directory. Edit it as root and then go back into the installer script again. You can see what it's going to do before you install...it should say that it's going to format with reiserfs.