I have decided to make a map with everyone standing in water of 1 for the height, but the water's black. If I up the water quality, I see water, but it crashes. How do I fix it?

do you have the watertexture in your worldfolder?

ya mean world1? Or effects?
EDIT: I also tried to make an oil refinery a cp, but my game crashes now no matter what.

What I would do is make a custom water. If you have done it correctly you shout have a water file in your "effects" and "world1" folder. You can copy other waters from other maps or just make your own... it isn't too hard. I hope this helped.