Shem is right, you have to select new game to play any DLC. This does not mean that you will have to play the entire game, just the new level you downloaded. This was the method established by the game producers to access the DLC levels.
There is no emotion, there is peace.
There is no ignorance, there is knowledge.
There is no passion, there is serenity.
There is no chaos, there is harmony.
There is no death, there is the Force.