If you are using Ideology, and you remove an apparel mod, you can break crafting benches because your ideo requires a missing apparel def.

to reproduce the problem...
start a game with ideology, pick a modded apparel for a precept, save, disable that apparel mod, load, vanilla bills are now broken because of missing apparel precepts

to fix it you need to edit your ideology and remove those modded items from precepts

go bug ludeon to fix this one cheers