I have indicated in Earth Exploder the coordinates I wanted the .dem dat file to be from/of they sent it. Instead of a .dem file they sent me a .kmz file, and SU fails to import it. WTF is the matter ?
SketchUp can only import KMZ files that contain a 3D model.
Anssi
Unzip the kmz, look at the kml, and see what you have. 