Actually, I think this has to do with Knoppix. If I am not quite mistaken, Mandriva 2009 could start the wlan itself, Knoppix 6.X can't. When I assign essid to wlan0, it's all ok, but then on ifconfig wlan0 up I just get SIOCSIFFLAGS: No such device. Hardware is recognised, but the right signal isn't sent, it seems.