http://pastebin.com/ayBxcq3k

Build 296 is the last one that loads, every build after that (I tried each one) gives the above pastebin'd error on client start.

ChickenBones' auto downloader doesn't seem to be working for whatever reason and as a result, adding a new function seems to be causing crashes for people as they do not have the latest WorldCore.

However, the solution (for now) is to delete WorldCore from mods/1.6.4 and let it redownload (which will download the latest version).

Thanks!