Screen gone black randomly?

[TheEmmasaur]

Hi guys,

I have a 1gb hexxit server, where me and one other play on it. I was playing earlier and then suddenly the screen went black (however the mini map and other hud elements were still there), and then it kicks me off with an error. I can get back onto the server but the black screen happens immediately. My friend can get on fine so I know it must be a problem my end.

Here is the crash report:

http://pastebin.com/9sLYCKqi

If anyone can help that would be fantastic!

p.s. we were trying to make a nether portal earlier but we had a problem where it didn't go to the nether but other random portals throughout the world instead. Could this be linked?