The iBook G4 12" 1.33GHz is known for having a problem with the airport/bluethoot socket on the logic board causing kernel panics events. Try to desactivate Airport and bluethoot and check if the problem persists. If the iBook works without problem after the desactivation then your airport socket is faulty. You may try to reseat the airport card but often the problem will reappear. The only solution is to remove the airport/bluethoot card from the logic board and use a USB wireless dongle as a substitute for the airport card or to replace the logic board.