No problem for me. Registered DKCR today (registered Luigi's Mansion and Fire Emblem earlier in the month) and was then taken through the steps to register my free game.|
Received a confirmation email a few minutes later stating that the download code would be sent out shortly after the release date (chose Animal Crossing).
You might want to check your registration history to make sure three eligible games are there. If they are, give Nintendo a ring.
#9592737, By Nintendo 3DS