I had installed the version compatible with the current forge in the modpack.
I had installed it as I had multiple times before with winRAR, by c/p the files from the optifine main file to my tekkit.hexxit.jar.
The only change I had made was installing Optifine, hoping to raise the general frames per second.
It crashes immediately after the Mojang screen.
The text file is right here: http://pastebin.com/6Y5kipzJ
I'm sorry if I am of little help.
I have recently been playing Hexxit, and have found much enjoyment from the series of mods compiled into this pack, but since a while back, I cannot seem to get the mod pack itself to work.
Here is the error message: http://pastebin.com/AuGfZKJy
I hope somebody is able to assist me on this matter, thank you for your time.