With the recently released version of MFR, WG causes a crash. More information available at the ticket over on the MFR github skyboy/MineFactoryReloaded#412 and my logs http://pastebin.com/TzsPgfhP (crash is forcing itself to available, so I don't have just a crash report -- just my latest.log).

EDIT: WG currently does work with the previous version of MFR, but the current release of MFR is currently not compatible due to this crash.

Disable nugget transmutation in the config