Sims 2 Double Deluxe - Registration code "invalid" when trying to obtain digital copy.

I just purchased The Sims 2 Double Deluxe and am currently having trouble with my CD/DVD drive recognizing the game disk.  I tried to use the registration code found on the back of my manual so that I could obtain a digital copy of the game; however, my code is not being accepted as valid.  Please advise as to whether this game is able to be digitally downloaded.  Thanks so much!