mantle does not support optifine, but that only tells us that they might be conflicting.
since field_71440_d is used by forge (it's not part of minecraft itself), i assume that this is a conflict between forge and optifine. now, i guess you installed optifine on top of forge, meaning that you used the optifine installer and selected the forge profile there.
what happens if you load the forge profile you used before the crash (the one without optifine)? if this work, install optifine by putting its .jar file into your mods folder and try again.