A minor glitch that prevented gamers from using an unlockable dashboard theme and gamer pictures in Jetpac Refuelled has been fixed with a new update. Rare released an official statement on its official site, acknowledging the technical blip, and apologized. To install the update you are actually required to delete the game you have already downloaded and completely re-download the now-fixed version.
Don't worry though, it won't cost you a penny, and your save game and leaderboard status will remain intact. If you're dubious of the whole process, Rare has kindly supplied a step-by-step tutorial. They're nice like that.