I have this same problem on my server. Crash every day 5x a day... I dont know if is the same error, but it is crashing all days after the 30.12 update. http://theindiestone.com/forums/index.php/topic/12128-yeahmultiplayer-is-pretty-much-unplayable-now-that-3012-is-out/?p=156251
In this new version 30.12, my public server crash 5 times a day with this message error on print screen image. I reinstalled the game, checked for update java, but continue with this problem...