PS3 will not load RDR or Undead Nightmare? HELP!?

So, i bought Undead Nightmare today brand new. I put it into my PS3 and it will not load. It comes up as 'Red Dead Redemption' and i select it, then it goes black and then straight to the XMB screen again. i have no idea what is going on. I tried every other game i own and they work perfectly! Inculding L.A. Noire as its a rockstar game, and that worked perfectly. It just seems to be RDR. Any help will be great, I have a 320gb silm PS3 HDMI.