This sounds like an issue I once had when ordering an old Ubisoft game off of Steam. A lot of those games require an additional CD key just like the standalone versions. I bought the game, but I never got my key! Until a week later. What I didn't realize at the time is that the CD keys are not generated on the fly upon being purchased. I thought they had their own software for generating them, waiting for somebody to buy the product. Wrong. They predict a certain level of demand and generate enough keys before-hand to satisfy it. It sounds to me like the keys are on "back order", for a lack of a better analogy.