I have a tail light bulb error and I've noticed that the front tail lights (on the passenger side) is flickering on and off, the 2 round lenses. I also have xenon headlights.

How would this be fixed?

To check its a tail light at the tail end of the car reverse up to a wall at night & switch all the lights on in turn remembering your brake lights. Then once you have done that turn all your lights off and switch on your front lights on turn you don't need a wall for this :).

If your headlamp is flickering check the connections if you're in anyway technical it is just a case if checking the plugs are in right. If this doesn't help check the bulbs are in securely. If you still have this problem then you might need to pop down to your local garage.