You have a mixin error from the ae2wtlib.mixins.json. this is not a sponge fault but rather the mod that provides the mixins.
It looks like the mod Restock but its difficult to work it out from the small log you posted. If its not that take a look at my program of Mixin Detector Program and then filter on that file above. It will tell you the mod.
Once you find the mod, take a look at their page. Maybe a fix already out. If not report it to them as a issue