Modpack Not Launching

[Original Icarian]

I don't know why, but the launcher won't launch the Horizons modpack. At first, I thought it was because the modpack itself, but when I click 'launch', the window I use to pick the modpack disappears for a few moments before coming back, as if I didn't click 'Launch'.
Pastebin:
http://pastebin.com/hj2me9d7

 

[Kliptic]

I'm having the exact same issue, with the error unable to load. Other modpacks load just fine, however horizons just closes the launch, keeping the console up, then it acts like it's booting up before it just reopens the launcher.

my pastebin regard the same issue as the OP
http://pastebin.com/fhU71t91