Dark Souls is reported to have quite the issue in regards to players trying to play the downloadable content.
Upon finishing the story of Dark Souls, the game saves automatically and forces the save into a New Game+ save. Normally, this wouldn't be a problem, but the DLC that's been released for Dark Souls has a couple of big prerequisites that need to be fulfilled. Since a new game signifies that technically nothing has been experienced, the DLC can't be played. These are the requirements to access the DLC content in-game:
-Defeat Hydra at Darkroot Basin
-Defeat Crystal Golem at Darkroot Basin and save Dusk of Oolacile
-Defeat Crystal Golem at Duke's Archive and get Broken Pendant
-Touch Black Fog at lake in Darkroot Basin where player defeat Hydra
Namco Bandai has gone on report in saying that there's no way to access the content without doing these things. From the way it looks, the time it will probably take to reach some of these requirements is around 20 hours, which really puts a damper on the experience. However, if you haven't finished the game yet and want to experience the DLC, now is the time to do so. If this issue has plagued you, feel free to discuss it in the comments below.