Serial: Invalid or Serial: Unable to be read serial number usually happens when your Lumina isn't directly connected to the computer with the USB provided.
To fix this, please:
1) Check that your Lumina is directly connected to your computer with the USB cable provided so that the serial number can be displayed.
2) Insert the email you want your license key sent to.
4) Check your email for your free license key.
Still not working? Contact firstname.lastname@example.org - we'll help you out!