There is no key anywhere as normally, no CD key is needed. The protection checks if the CD is not a copy. If the protection fails, you have to request a key by contacting us.
Also, if you have more than one CD or DVD drive, the protection might require you to insert the CD in the other device. Have you tried this?
If the protection check still fails, click the "information" button and mail the generated report to our support team:
support@larian.com