A few guys i am talking to gave me a crashrepot:
http://pastebin.com/8a0CqGyY
That happend after clicking in the assembly table something to activate the crafting.
I do not know what went wrong there. They use the latest (1.7.10) public released version of bc.
Also this bug distroyes worlds so after activating you need to reset the world or use the forge thingy that remove broken tileentities.

Edit:
Note this bug came after updating BC.
And yeah they have huge pack <.<

caused by an outdated BC api, probably dragonAPI is responsible but there might also be other mods