With the fuel lid open push on the remote button while you watch the black plastic rod - to see if it moves. If it does not move then the solenoid is bad or it has become disconnected from the mounting bracket.
All year Boxsters have only one working rear fog light, on the driver's side. There is more info on the UK board.
http://forum.boxa.net/index.php?act=ST&f=4&t=1075&hl=fog+light&s=
Why just one? Some say so the driver behind you will not think the brake lights are on. Some say it is so the driver behind you knows which side to pass on. Jeff