Why can't I register the content pack which without the serial number?

Now Reallusion register mechanism only provide to register the product which has the serial number.

As for the content packs without a serial number, if you lost the installer you will find the download link in your "Order" at member page. May refer to http://kb.reallusion.com/General/50021/How-can-I-redownload-the-program-if-I-lost-the-installer.

If you cannot find them, please just contact our Support Team and provide the transaction information that we will re-send it to you.