Working with the latest beta1 release but I had the same problem with alpha2. I've uploaded a simple KML file on my dev server. The KML is really simple and validates for error – just a simple Point location. I've created a KML layer with a link to my KML file on the same surver, same subdomain as the test. I've added the layer to a map with display style (that works for displays other layers). But my KML is now showing up. It does show in the layer switcher but the point from my file is not visible. Map projectio is 900913, display projection is 4326.
Am I doing something wrong or missing something? I've wasted many hours already starting from more complex KML files and now with the simplest KML with a single point in it. But the KML file does not seem to be the problem here.