I had the same exact problem with attack of the b-team. http://pastebin.com/RbUDqRbQ
Edit: i just realized that the log cuts off as soon as i start to download attack of the b-team....
Hey! The specific problem I'm having is that when i go to download a mod pack (even vanilla) it downlaods everything then stays at 0% for examining version file forever.
Here are my logs: http://pastebin.com/ZMgMCnGc