It's actually the other way around, you register at the website taht Moremiles provided, then that will take you to the download screen.

However, you MUST call PTO at 1-877-423-2288 to ask them to add you Aeroplan number to the database before you could use it otherwise it'll just keep telling you "invalid account number". Exceptions are when they send you the CD then that means you are already in the database.