Open 1.2.0: Not Able to Load Single Player Worlds

[AdmiralNarwhal]

Version:
1.2.0

What is the bug:
The mod pack loads up fine but then when I load up a singleplayer world it immediately brings me back to the main title screen. I also tried making a new world but that didn't work either. I have no idea what else to try.

Mod & Version:


Paste.feed-the-beast.com log:


Can it be repeated:


Known Fix:

 

[NunoAgapito]

Crash log?

 

[AdmiralNarwhal]

Here's a crash log.

And also when I started up the launcher there was a notification that says, "Error extracting native libraries" and then proceeds to crash the launcher.