Aberrant

It looks like it's already fixed by the IC2 guys.. no idea when (if ever) that will roll down. Will probably fix itself in a few days though (looks like it's keyed off some "seasonal" flag.. which probably gets unset after Halloween).

There is a thread happening elsewhere with more details on another forum: http://forum.feed-the-beast.com/threads/exception-ticking-world.33617/ An effective workaround for now appears to be setting difficulty to 0 (peaceful) and spawn-monsters to false. The bug appears to be in a chunk of code that does some funny stuff when mobs spawn, so this prevents that from happening. This got my server back up and running!

You arn't the only one. Apparently this is some IC2 seasonal content and is taking down tonnes of servers (including mine): http://bt.industrial-craft.net/view.php?id=431