Night lights problem

I have tweaked my night lights many times over by now.I finally installed FSW's night lights and yellow set of runway lights, but there is something that bothers me seriously.The runway/taxiway lights glow like a moon. There is a bright shadow around them causing runway lighting to look like a big white bulb from a distance. It looks like I overdone it. Do you have any idea what might be causing this phenomenon? Is it my video card failing to display as it should, or is it the actual light texture files corrupted?Thanks for your help.Don