SketchUp 2013 requires a license file no matter whether you have the Pro version (license file contains Pro license key) or the free "Make" version (contains agreement for non-commercial use). While SketchUp 8 tried to make the executables more different to prevent licensing problems, they reverted that and made the executables almost identical, introducing a lot of new problems under certain circumstances (Make turns itself into expired Pro, refuses to run more than 1 instance, or refuses to run as "portable" app).
I assume the above problem was due to user/admin priviledges (in an ideal world, programs would absolutely never request you to run as admin). Strangely the license file is sometimes located at different places, like Users/Public/AppData/SketchUp/SketchUp 2013/SketchUp13.lf which is writeable with simple user privileges. Maybe SketchUp will also find it when you move it there?