Ultimate Pack Freeze During World Creation

[bluechance12]

Alright, so the ultimate pack just came out and I wanted to go try it out (the other packs worked fine for me). So I load it up and head to make a new world. And it loads to where it says 'Loading World Converting World'. And then it just stops, still saying converting world. No crash, just nothing happens. The last thing the console reads is:

[Minecraft] Starting integrated minecraft server version 1.4.7
[Minecraft] Generating keypair
[Minecraft] Converting map!
[STDOUT] Scanning folders...
[STDOUT] Total conversion count is 0
[ForgeModLoader] Loading dimension 0 (Test) (bdz@768f310f)

Nothing else after that. This is a brand new world, and Ive used the other modpacks fine in the past. I have the memory maxed. Any help would be appreciated! For the full log:
http://pastebin.com/bVBgMX1v

Oh, and if it makes a difference, I'm on a mac.

 

[ArthurPDent]

I'm assuming your running Lion or Mountain Lion on your Mac, as everyone on those has been getting this error. It's caused by a memory error in Java, luckily it's been solved try this: http://forum.feed-the-beast.com/threads/detected-leaking-worlds-in-memory.12098/page-7#post-157630