Actually there is a registration page, it just occurs in the ding application rather than registering before you download.

Update Registration would indicate that you already had a registration which you were updating. Updating is changing your airport selection.

Once you have downloaded and installed, the first thing that appears in the ding window is the registration process. You choose up to 10 airports, enter a Rapid Rewards number (if you choose), and then click "register".

You cannot receive messages, or update your registration, until this initial registration process is complete.

Until you have registered, this should continue to show up in your ding window. If not, try closing ding (right click EXIT) and then re-opening it from the Start menu. As soon as it opens you should see the registration process in the ding application itself. Scroll down in the ding application window to complete the process.