"Changer Parked" message

I have a 2007 Pontiac G6 convertible, and I had the battery die (external lights left on). After jumping the car, I have had the words "changer parked" pop up on the radio when I unlock the car and open the door, prior to putting the key in the ignition to start it. What does that mean? How do I get the words off the radio (reset the message)? It disappears after about 5 seconds.