r/minecraft, I've tried everything. Please help.

I recently decided to learn how to write mods for minecraft. I kinda failed. So I deleted my modded minecraft.jar and tried to force an update. When I try to force update, I get this: http://i.imgur.com/Qdvl3.png

I've tried deleting my entire .minecraft folder and I've reinstalled java. Nothing has worked. If you could help me that would be great. If you don't know how to fix the problem, an upvote would be greatly appreciated so that someone else might be able to help.