How do I manually open the disc tray on my Panasonic DMR-EX83?

I put a dvd disc in to the disc tray and closed it with the open/close button, but the open/close button will not re-open the tray to allow me to remove the disc. I have turned off the power at the mains to allow the unit to reboot which usually produces the message PLEASE WAIT which flashes for about one minute. This time it flashes indefinitely and does not go back to normal operation mode.