I've installed some mods, mariculture is one of them and seems to be some kind of trouble when the world is generated. I've tried to find which mod could be the reason of the crash and when I disable mariculture the crash does not happen anymore.

Crash report: http://pastebin.com/engunXjh

Other source:
http://support.feed-the-beast.com/questions/3650/a-different-crash

... dw20 base i assume. Change Ravine chance in worldgen.cfg to 25.

Yeap, was dw20 and I changed the chance, I seem to work!! Thanks, I really wanted to play with Mariculture, and I was thinking by that time that I wasn't able to, that's why I submitted the issue. You just made my day, thanks again