Sun Flare Isn't Showing Up

Ive been working on the same project forever because I’m biting off a bit more than I can chew. I cant get my sun flare to show up in my render. Its on a different render layer and I’m using nodes. Also, in the node preview the flare is black. Why is that? Everything is set so that it SHOULD work.

Grass.blend (884 KB)

The only thing in this file is a plane with grass on it, and a lamp. I see nothing as far as render layers set up, or anything that would give you a flare.

For whatever reason I cant upload the updated file. I dont want to give up but right now I’m not really seeing a way to move foreward. I put the sun on one layer and the grass on the other. When I render, I see the sun until the grass scene renders over it. And the sun is black rather than lit. I really wish I could attach my file for you to look at.