Logs: http://pastebin.com/6jAK03X3 this is my run on vanilla 1.7.10 before downloading forge. Don't think it will help but whatever
First I used the launcher to download forge. It said "These libraries failed to download, try again." So I downloaded fmllibs16.zip and extracted it into the .minecraft folder, then I tried to download forge again. I got the same message.
Here's the full error log: