I built a turbine, and the multiblock formed, but I still get this message. Im running version 0.3.4A2 on 1.6.4.

I have no idea how to recreate this. Its on single player and it was built creatively.

The empty block Im looking at is the block that the error is at.

There's probably some other mod in your modpack making invisible entities. Some mods do this to permit tracking of player locations or other features. Unfortunately, it's not really "standard" or friendly behavior.

Nothing I can do about that, sorry.

Solved the problem. I built part of it with WorldEdit.