UE3 - UT3 lighting problems, help plz :(

hello, i'm having some trouble setting up lights in my map right now.
the first spot looks like this:



you can see that the yellow light for some reason stops at that seam even though in the bsp there is no seam. it's one flat surface.

something else:



you see that the row of bright blue lights on the right actually light the wall while the exact same row of lights on the left don't. doesn't even matter how close or far they are from the wall, what brightness i give them...

last one:



here i get this orange light even though there's no orange light around that spot and i don't have a orange sunlight or anything, either

so if you know what's wrong here i'd really appreciate some help

UPDATE

i found the problem. and just so nobody runs into the same weird thing: the rain meshes from the UN_Weather package have castshadow enabled by default. this causes all the stuff above. i didn't think of it earlier because i added the meshes to a group to be able to hide them at the push of a button and they were hidden of course... also, these meshes use projectile collision by default.