I'm studying this map in the new version of the UDK, i think it's really good and a perfect example of outdoor lightning, but...i found only ONE light, a dominant directional light, is that possible? all the details and the shadows are created by this only light? i don't think they are created by emissive materials
If i try to create a scene with some Static Meshes and only a DominantDirectional light i have no light and no shadows.
try looking at Global Illumination and other lightmass settings. i suggest starting with Hourence's intro to lightmass.
Are you on lit mode? Some times I get a bug even when I place a light it doesn't switch automatically to lit.