if you want to use airsnort with an orinoco card, you need to patch the orinoco drivers so that your card can be put into monitor mode. wow, im surprised nobody flamed you guys and said 'this has been said before', but i believe forums are meant to help people not to tell people to do searches, so here is a link
http://airsnort.shmoo.com/orinocoinfo.html
also, ive never used knoppix before is it a read only FS? if so, i dont see how youre gonna be able to apply this patch.. or i could be wrong and everything will work fine. good luck.