When I take pictures of people, the yellow and red tones seem to be enhanced and the result is a more jaundiced complexion in best case scenario and orange and a bit shiny if their skin is a bit oily. This only occurs with flash on. Is there anyway to remedy this situation, because sometimes I need flash on. Could it also be the orange autofocus light's fault?
Its unlikely to be the autofocus light, unless something is broken.
Its probably really white balance. If you shoot raw you can correct it in post-processing fairly easily, which can keep you from having to throw out shots that have good expressions.
You can try using a piece of white cardboard (say an index card) to redirect the flash up onto the ceiling, if its painted white. Do it as an experiment, just to isolate the cause. Of course, if the ceiling is purple, then expect a purple cast to the photos.