Well, I uploaded new version of the game, with disruptor & disintegrator, and the server crashed half an hour later.
It is possible that it is due to new actions.. but I really don't understand why :( Ultraswordsman claims, that he was just using disruptor when it happened (he attacked flying slime). I tried to reproduce it.. but it works fine for me. I really don't know. My code looks good. Let me know when you notice something.