Problem Ultimate Server Crashing MCPC+

[mocfunky]

So my server has been running fine an all the sudden http://pastebin.com/GvBLRMDY

It does it about every 2 hours. I have had crashing problems before but never seen this before.

Here is what I use
MCPC+ L15
Ultimate Pack
Ubuntu 12.04 64 bit
McMyAdmin

 

[mocfunky]

I noticed this

1. Console : at twilightforest.TFFeatureCache.save(TFFeatureCache.java:120)
2. Console : at twilightforest.world.TFWorldChunkManager.saveFeatureCache(TFWorldChunkManager.java:415)
3. Console : at twilightforest.TFEventListener.worldSave(TFEventListener.java:429)
   So could it be twilight doing it? Any known problems?