User blog comment:Otakon7/Otakon7's Buddyfight Simulator/@comment-24971427-20150613141253/@comment-2234004-20150613143227

Works fine for me, so it could be something else that the reason for the error.

Take a screenshot and post it here.

P.S. make sure you re-add cards that have been fixed lately, since having old versions in your deck can break the sim.