Down Rodeo said:
It's too big/you don't have enough RAM/you need to increase your swap size.
Fixes: make the map smaller/buy more RAM/increase your swap size.
I'd recommend the middle option as the first, well, it kinda changes your map, and the third will just make it horribly slow. The second would give you a bit of a performance boost elsewhere, see?
How do i increase my swap size?