Are these bugs in the tracker? Which action was crashing with no meteorites? (It ought to handle zero objects fine)
I'm not exactly sure, it was hard to reproduce... but involved an event matching multiple objects in the condition, then referencing one of them in the actions, then deleting it (which instead of deleting one, deletes all of them in that call, which in turn messes up the remaining calls).
I think I can whip up a test case now. It's not in the tracker, I just figured it out.
EDIT: crash is still there apparently it's unrelated to the explosions thing, which is fixed.