Dear Joseph, Dear Stig,
I followed the steps outlined in the Aperture Inspector FAQ after the app only showed the splash screen with the magnifying glass (no library could be analyzed). After having deleted all aperture inspector related files as proposed the relaunch leaded to a dialogue to appear announcing that Aperture Inspector had been updated. So far so good.
I relaunched the app but the program version was not 1.5 as expected but 1.2! I had to re-enter my serial number (Guess that's just because of the deletion process mentioned above).
What can I do to update to 1.5?