Single Player Map Not Loading

[Munda]

As far as I know I didn't change or do anything different, but my single player world suddenly stopped working. I tried taking the world over to a server and got the same problem. It just hangs in the loading screen. I tried waiting as long as 20 minutes and still nothing. This is what was in the crash report folder. Sorry if it's not the right thing to post, if it's not please let me know and I'll find the right file.

EDIT: Must've been some problem with a mod or something, Updated to version 0.5.4 and it's working again, so yay! Nuclear meltdown, here I come.