I am not from Laminar Research; just a flight simmer from downunder.
I have the boxed set of DVDs from Aerosoft.
To run the dvd version of X-Plane you have to have disc 1 inserted in the DVD drive at all times. There is no registration key required or supplied with a disc version. There is no USB dongle available as a replacement for disc 1 as there is for X-Plane 10. The alternative is to create an ISO disc or a ISO USB dongle (consult Dr Google on how to create)
The so called registration keys supplied with the aerosoft DVD package on a aerosoft document is a "ploy" or "con" or "enticement" to encourage you to purchase other Aerosoft products at a discount rate. It has no impact at all with regards to running the DVD version.
At the time I installed the boxed set I had the same problem you are experiencing and contacted LR. There advice is exactly what I have advised you.
Use the advice I have given you and it will work.