Is it possible this is related to the directory? Windows can be very particular about some (Program Files, obviously, but also the My Documents sometimes, depending on if you the user account is administrative).
The CubeItMod guys will know more about it than I do. If changing to a random generic directory doesn't work ("C:\KISSlicer_equals_42" is always a good choice [8^), does logging in as Administrator change anything?
Jonathan