RESOLVED(for real this time) : See Edit 3.
I have been having a similar problem with Direwolf, where my game crashes halfway through trying to load my world. I managed to resolve it by deleting both FTB *and* my MC folder, but I've documented other details below.
First attempt not recorded, but simply stopped during the "Building Terrain" phase, at about the same point where the third attempt crashed. Didn't freeze, just didn't continue the loading process.
Second attempt pastebin :
http://pastebin.com/GiKV5xEu. Also just stopped, but the log continued a little further than the first attempt.
Third attempt pastebin :
http://pastebin.com/AmNz3fej. This one actually crashed.
After the third try I attempted to recreate the world using its seed(it crashed) :
Pastebin at time of crash :
http://pastebin.com/aaDxyXbA
Console continued for a few moments after the crash, so here's that too :
http://pastebin.com/LtpQxucM
Additional details :
I had some trouble downloading(this turned out to be a timeout problem caused by my rural internet). Eventually I managed to complete the download, and the game launched(with all the FML setup and everything, because at one point I had completely deleted my FTB folder, copying the saves directory elsewhere, to try and clean up my download problems). Once it loaded I went on to try and load my world, with the problem noted above. On my second attempt at launching the game FTB Launcher insisted I needed to update Direwolf(despite having downloaded it fresh 5 minutes earlier). I decided to refuse, and the game loaded. Second attempt at loading my world noted above. My third and fourth loads of the game followed the same steps as the second and the results are noted above on my third attempts and fresh-world attempts.
Afterwards I decided to copy my entire Minecraft directory + FTB elsewhere and redownload everything from scratch. Some time later, my internet gasping and wheezing from exertion, I reached the main-menu screen.
Here is the console pastebin at that point :
http://pastebin.com/q3ceh2Ek
I include this pastebin because it ends on an error, about a 503 response from an Amazon server.
Finally, here is the pastebin after it finally managed to successfully create a world :
http://pastebin.com/Cv05UbwZ
There are still some weird problems...I don't appear to have sound, for instance, and I saw a number of errors in the console. The game *still* insists it needs updating when I run it. A fresh copy of my original world will run, but not the original itself...I suspect it got corrupted when I kept trying to load it.
EDIT : Good news! Not resolved at all! Or rather, I think I know what was "breaking" it to begin with. After I tried to load my original world any attempts to load or generate worlds with that install resulted in a crash. It seems that loading the damaged world corrupts the installation.
EDIT 2 : Well, further attempts to re-redownload the mod have lead to repeated failures. Maybe certain parts are failing to download correctly? My last attempt kept crashing, usually with an error about the Chicken Chunks mod. I'll continue experimenting.
EDIT 3 : Okay, the guy in this thread :
http://forum.feed-the-beast.com/threads/minecraft-crashed-and-now-crashes-when-loading-world.11123/ figured out that you need to run your launcher in admin mode so the game can make the necessary files. So problem solved.
