CD Projekt says they will address the Troll DLC problem in the next patch specifically here.
- Fixed the free Troll Trouble DLC download. It is now included n the patch so there's no need to download and install it separately
They claim the patch could be available as early as the evening of the 25th (which is like right now).
If you're playing the Steam version, I image you'll have to wait until the patch is rolled into an auto update.
Keep in mind that if you advance beyond chapter 1, the troll quest won't be available on your most current file (at least I can't see how it could be).