Which kernel are you running? In other words, are you using "knoppix26" to use kernel 2.6 or or "knoppix" to use kernel 2.4? "myconf=/dev/sda1" should work for kernel 2.4, but kernel 2.6 seems to have moved to "/dev/ubxy" (in other words, /dev/uba1 instead of /dev/sda1) for USB keys.