Imei number on samsung galaxy s?

i purchased a samsung galaxy s phone two days ago. i then tried to fill in the promotion form on claiming £50 worth of games and movies on the samsung websitea href="http://www.samsung.com/uk/galaxys/promotion.html#" rel="nofollow"http://www.samsung.com/uk/galaxys/promot…/a , it say my phones IMEI number isnt recognised. can you help me?