Brakes? Please help.

I have a 2002 Venture. Lately, when I apply the brakes I get a jerking motion as I am stoping. I don't feel any pulsating or anything weird under the actual brake pedal where a brake problem is normally felt. The braking ends up being very "choppy" and it makes me move back and forth while sitting in my seat.
What can this be? I had new rotors and brakes installed 2 years ago.
 

Hi, that sounds like possibly warped rotors or some other reason the pads aren't seating equally when braking.