There's your problem right there. Take the filter off, especially at night.
Yea, i wrote that i tried that aswell.
No change.. 
Edit*
the UV-filter have been on the lens since i bought it (brand new) and as i stated earlier.. i havent seen this before, and i've taken lots of photos in dusk, straight at the sun, dawn, at lamps, in welllit rooms and so on..




