i get this huge error
Why do you think this has anything to do with "Could not reserve enough space for object heap"?
Please use the report format.
And please search the forums to see if your error has happened to other people, which in this case it has, in fact it's stickied on this board right next to this post. You need to install java 7. That or disable the offending mod, in this case, nether ores.