Invalid state engine for a tile entity and removed entity problems

So I'm working on my mod Compact Mobs, and I've run into a problem. My compactor finds the closest entity in a bounding box, and then extracts information to save to an item in its inv. Recently, I have noticed that the compactor is compacting twice for the same entity, even though it removes the entity from the world at the end of the first compact.

I tested, and it is running twice. I did a printout, and the mob is being removed but the compactor's Do Work method (using the buildcraft power interface) is being called twice.

In my attempts to fix it, more specifically, setting it dead as well as removing it, then making sure I'm only using alive entities for the compact, I have run into this error:

http://paste.minecraftforge.net/view/0ff62611

I kinda felt that the problem was being caused by minecraft ticking the tile entity wrong or the same code being run in two separate threads, but I'm still not sure.

If anyone can help, that would be great! I want to fix this before the 1.5 update so I can get an update out.

Also, the for the compactor can be found here (although it is a bit messy... I was in the middle of trying things):

https://github.com/itsZN/CompactMobs/blob/master/TileEntity/TileEntityCompactor.java

-itsZN