Oh dear, now I'm laughing. Well, this thread is about another variant of VNC viewer. I consider this my personal "official version". Otherwise I think you a) should more carefully look at the page you linked, and b) should - before emailing - read the setup guide on that page carefully as it contains hints on what you're expected to do to get the full version.
However, the linked guide leaves me puzzled. Why is it asking for the Kindle's serial number? I would _not_ suggest to disclose this to a third party!
Shameless plug: I think there were people who tried out that VNC client and stated that it was much slower that kindlevncviewer (which this thread is about). You might want to read the first post in this thread and just download a full version. For free, BTW.