There are no firewalls set up by default on knoppix. You should do this. Make sure your card is detected. Look at the output of lspci from a shell. Does it show your card? You might also look at the output of dmesg. Double check the network settings you are plugging in. If this all looks good, then check the cable you are using from the machine to the router. Is the cable good? Are you using the right kind of cable: straight ethenet? crossover? I'm not exactly sure how you have things set up so you need to check these things out.