Braking Problem

Hello,
I have a problem with my brakes after the vehicle has been sitting for a while..like overnight or even a few hours. when I apply the brakes during the first few minutes they lock up when i just touch the pedal ,after i hit the brakes a couple times its ok. I had all new brakes put on the van last summer. any ideas?

This happens to the rear brakes, or the front?

I'm betting on the rear. If so, the shoes are either bent or binding inside the drums, and it REALLY should be fixed ASAP, as driving it this way is very dangerous.