Not able to write a review

Every time I go to write a review I get the message, "You are not allowed to write a review". Can somebody please help me?

what game are you trying to write one for? also, have you rated the game already? some more details would help. Thanks.

I have the exact same issue "You are not allowed to create a review"

Game is Interstellar Marines ... and no I hadn't reviewed it before. It won't take my point score or let me Write a Review.

http://www.gamespot.com/interstellar-marines/