The email you get from https://www.stardock.com/support no longer includes certain serial numbers for fraud purposes. To look at your serial number for a game, right click on the Impulse entry, and click 'View Registration'. If the game isn't in Impulse, make sure you are using the correct account info. If you are, try closing Impulse and running the following file:
http://sd.stardock.com/curthendzell/fix_registrations.reg
Make sure to follow the link in Internet Explorer, as other web browsers will not handle the file type correctly. Once you follow the link, save the file and double click it to apply it. Then relaunch Impulse. You will need to re-login with your username/e-mail (either will work) and password.
espontaneo: I'm looking into your issue now.