I'm not exactly good with coding and such, so I was hoping to get some help.
Crash report here

You are in a not loaded world. Move your location to DIM28.

I'm sorry, could you tell me how to do that...?

Download NBTExplorer, open your playerfile with it (can be found in your saves//playerdata) and edit the "dimension" entry.
Make sure to backup your player file as you might be stuck in the ground depending on the coordinates.

Another crash log... http://pastebin.com/5Gi7UYzX

I'm sorry. It didn't change anything then.

That's the same crash.

Can you reopen the player file and post a screenshot?

Try deleting DIM2 folder in saves.

No change.

Disable RandomThings mod then, the mod is trying to create a world which already exists.