quicktime 7 pro

I have just purchased a registration key for Quicktime 7 Pro for my Macbook running Yosemite (Ver 10.6) ...After following the instructions to cut and paste the registration key into the application and hitting the tab key I find that the cursor simply cycles through the three fields and the QT logo doesn't acquire the 'Pro' graphic and the QT7 application offers no extra features. Can anybody help? What is this user doing wrong?