Ive purchased & downloaded content for Skate 2 on Xbox 360, how do i install it? Plz Help!!?

i purchased the Rob Dyrdek's Fantasy Factory downloadable content and downloaded it, but i haven't been able to play it. when i goto downloadable content on Skate 2, it says that i have downloaded the pack, but it is "Not Installed". ive never had to install downloadable content before. i also have the Free Throwback pack that is in the downloadable content section. i downloaded it weeks ago, but it also says Not Installed and doesn't work. plz help! :)