halo 3 skull help?

[Cheese F]

i picked up the skull on the ledge on the first level then took it to the end of the level died a couple times then got on the pelican with it why wasnt it unlocked?

 

[pixeldamage]

Double check to make sure it didn't unlock. All you have to do is pick it up, you don't have to carry it to the end of the level.
Check out the link below.