DVDFab does not sell anything called dvdfab burner! Can you provide the website purchase link? Also have you tried joining the DVDfab member section on their website using the email you used to purchase the program with.
The member section will tell you what you have and when it was purchased and for how long it good for.
registration key issues would have to contact DVDfab contact us on their website as we are all users just like you and not DVDFab staff