So I bought Object Desktop, but didn't have any kind of Stardock account when I bought it as I had no idea this site required accounts.
I paid for this item (Object Desktop) using my PayPal account.
Got a screen after paying, which had all my purchase info on it including the Product Key.
Installed the installer for Object Desktop, then discovered I needed a Stardock account, which I made. However this meant that your site didn't have any purchase info for me.
I went into my account after verifying the mail, tried to apply my Product Code on the "Register Product" page for this Öbject Desktop" product, and get this error message: