I'm not certain what exactly is causing this crash as I do not use buildcraft, but downgrading to mek build 122 or throwing the buildcraft 6.1.8 api in my mods folder does seem to stop the crash from occurring. Initially I suspected the crash to be a conflict with ender io's recent buildcraft api update, but looking further at the log I see extra utilities mentioned and am left clueless. Thank you in advance...

http://pastebin.com/jMgkWzDC

I found I had this problem, and when I looked through my mods I only had 2 that included BuildCraft integration of some kind.

I had RailCraft 9.2.2.0 which I updated to RailCraft 9.4.0.0. (http://www.railcraft.info/version-9-4-0-0-the-rf-update-and-laser-rails/)

I had EnderIo 2.0.8.221 which I updated to EnderIO 2.2.1.276 (http://minecraft.curseforge.com/mc-mods/64578-ender-io/files/2218555)

Both of these mods have updated their BuildcCraft integration. Updating both has resolved my problem without installing the BC API.

Oops, that was me, yeah. I'll fix this as soon as possible. Until then the BC api is the way to go.

I believe this was fixed, correct me if I'm wrong

You are correct, works perfectly. Thanks:)