Hi,
There is a bug with Galacticraft that makes the game crash when you try to enter the Erebus.
Here's the crash report:

http://pastebin.com/vpB7ESWx

Hello,
Looks similar to this. Try changing Erebus' biome IDs.
micdoodle8/Galacticraft#1342 (comment)
Cheers,
Me.

Ok thx :)