With Darkrai, its Poke-Power is pretty much saying that when you put on to the bench, you can choose for either your active Pokemon or your opponent's active Pokemon to Sleep.
You can't put your own Active Pokemon to sleep with Darkrai MD. It says "1 of the Defending Pokemon", so that only applies to your opponent. Go fix and edit it.
(Posting here on your wall since I don't think it deserves a post in the topic.)
Brave Vesperia, Okay sure, I might be at a League from 2-5, but after that or maybe around 8amish I should be open (yeah I'm going to be out almost all day )