Crashing from chunk pop.

Crash while populating chucks without any blocks. I believe its crashing when it tries to place a tree, and there is no block, and just void.

Gives error of: "Ticking memory connection" If joining the world, and trying to load those chunks, and gives error of: "Exception ticking world" if you join in world away from chunks, and you walk/run/fly to the chunks that it is trying to populate.

The attached are a few of the crash reports from this. You will see that they either give the error of "Ticking memory connection" or "Exception ticking world".

You may notice: some are in 14w11b, and others are in 1.7.2, and others in XRay, that is 1.7.2, with the xray mod. World is "PVP World" this is the world i am making a large donut shaped pvp arena that is floating above the void.

I fixed the problem by putting a layer of bedrock under the entire arena with mcedit. After i did this, the world would load those chunks just fine.