Occasionally, when I try to start my 2005 Prius (196K mi), it does not start, and on the screen I get this message: "Transmission (P) lock mechanism is erratic. Park vehicle on level surface and fully engage parking brake." The dashboard lights go on, but there is no square around the "P". Since I am usually parked on a level surface, and can't start the car to change its position, I keep pressing the start button. After trying for 10 - 20 minutes, the control panel shuts off, and then the next time I press the start button, it starts and I can drive with no problem. Sometimes this happens when I have left the dome light on for 15 minutes or so. I have original batteries. Might this be a battery problem?