An OT can crash for a lot of reasons.. I've had a server crash from bugged vocations, bugged skills, bugged players logging in, lua scripts, house crash bug, just using windows (went stable after switching to linux with same rev+data files), bad server rev and sometimes its crashed while i'm in by myself afk..
You can make it more stable by checking each script, trying different server revs and making sure the common crash bugs are fixed if you're using a outdated tfs. Then just monitor your server carefully, maybe you'll find out whats triggering it.