Hmmm well I guess it's time to point out one of the house rules that apparently hasn't been adhered to much.
RTJ / Character Creation:
In combat, if you roll a 1, roll an additional d6 to see how bad you fumbled. Hint, don't roll a 6.
1-4, nothing happens except you missing.
5, and you fumble, generally losing your weapon at your feet or something similar.
6, and gods have mercy on you.