I've downloaded the map for Agrarian Skies but it doesn't show up in my single player worlds. I've looked in my save file and opened it up, for some reason the only thing the save contains is something called "version". Why isn't it working?
This seems to happen sometimes. You can download the map manually at http://minecraft.curseforge.com/worlds/77137-agrarian-skies-home-sweet-home-b/files and extract it into your saves folder.