Adding some relevant information in regards to the Metallurgy mod.
(Metallurgy-1.7.10-4.0.6.80, MetallurgyCore-1.7.10-4.0.4.18)
In the Metallurgy.cfg file near the very bottom, if you change the Sets values to false, it will throw errors during loading:
[08:27:42] [Client thread/ERROR]...