i appear to have just cracked this problem, i was getting the same purple colour issues at night, ive just changed the bulb in my main light from a bog standard pearl bulb to a energy saver and the problem is sorted, it looks like the pearl bulb was chucking out loads of infra-red which is what was overloading the cameras sensor.
i noticed that if i pointed the camera at the computer screen or my tv the picture on them was coloured correctly, turned off the main light and used the lamp on my mobile and colours were fine.
Change your light bulbs and you will hae a properly functioning camera without having to mess about with firmware etc.