when booting knoppix, try disabling the USB support.

so, press F2 when booting, then type
knoppix nousb

at the boot prompt. That will likely get you past the usb issues. Your machine probably has an older usb chip on it.
I have the same issue with knoppix 3.4 on my toshiba laptop.. have to disable USB support. There are commands you can run after bootup to have linux probe usb, but that will take more googling.