Big Patches of Black

If it doesnt show up:https://www.dropbox.com/s/kr7lyf3xi6v0iv9/black.jpg

I rendered a map in fast mode, but this never happened until now.I built cubemaps to see if that would do anything.It didn't. Anyone know a solution to this?

put the link to it,or you can right click open in new tab-that will sometimes work.

I hope it doesn't have a leak, I checked for problems.it is also a valve map I'm redoing for Christmas for our clan server,so I didn't touch anything besides gametype entitys and textures.