Why won't this work, am I doing something wrong?

I just bought the Nikon ML-L3 wireless remote shutter realease for my Nikon D3100
But it won't work do I have to buy something else that goes on the camera

http://www.nikonusa.com/...ared).html

You have to be in front of the camera (facing it) for the ML-L3 wireless remote to work. Of course, all of this is fully explained in the Owner's Manual for the ML-L3.