I can't double check it right now since I'm at work, but if I remember right, it said it was an engine error.
Weird thing is that it worked fine before the last ninja patch (the dll version before 8.0). I was using a bot that I wrote myself and it worked flawlessly through Sunday night and when I tried to run it last night it was fine when I went to sleep, but this morning is when I first ran into the problem. What I can't figure out is why it only crashes some of the time. It will work fine a couple times and then BAM Access Violation when I least expect it. You'd think if Nexon had done something to those commands specifically, it wouldn't work at all.