Blue and Pink stains in certain areas of the render

Does anyone know why I get these blue, pink stains when I render this image with artificial light? It seems related to the way the material (brushed aluminium) interact with the lights. When I change material with a non-glossy one and get rid of the lights I get a clean render. It happens only in that particular area. Please see attached screen shot.
Regards

one of the reasons that is possible is that one of the maps in one of your materials has a high rgb out or rgb level value. with GI and with LWF this can cause these kind of artifacts.
Try resetting the output amount and rgb level in the map to 1 and try.
also if you could load the scene i might be able to help you better.