Giveaway finished... but no winner or entries

I had the same problem with the same DLC ... It's that not many people have the base game, and of those who have it, a lot have already won the DLC as it's been around for a while now since bundle a couple of weeks back.
I finally got a winner, I think it was in my third attempt to give it away. Just do it at lvl.0 and give it a couple of days, and try again, if you don't get a winner.