ok i will explain.
i normally hate registry and never have any of my programs put anything there.
but i got a bit playful when i was writing license key system
the empty key sounds like a bug, i will check.
the other key is saving the installation date of the program.
when you install the program it saves the installation date in app dir and in registry and in a file in windows\system.
if one is missing it will recreate it on the next run.
basically its designed to be redundant to foil people who try to reset the installation date.
kind of silly since the donationcoder programs are not meant to be protected so much, i was just getting creative when i was making license key tool.
maybe i will remove this in next versions as it seems it does not have much point.
by the way, the program will not care if you delete it, no bad things will happen.. but it will recreate it on next run