On my G4 desktop running O X.2, several months ago, I had several crashes which displayed the same message you have seen. They occurred when I attempted to awake the computer by brushing my fingers over the keyboard and striking several keys sequentially, rather than pushing just one key. The crash was unrepeatable when I deliberately tried to duplicate it. I don't know if this has any bearing on your crash or not. The problem, unsolved, seems to have gone away.