Some people have had trouble getting their registration to “stick” on Intel based Mac computers (it asks for a keycode each time you open the plug-in), if this happens to you try this:
Delete ALL the prefs related to every Wave Arts plug-in that may appear in your username Library/Preferences folder:
FinalPlug 5 Prefs
Power Couple 5 Prefs
Power Quartet 5 Prefs
Power Suite 5 Prefs
Power Trio 5 Prefs
MasterVerb 5 Prefs
MultiDynamics 5 Prefs
Panorama 5 Prefs
TrackPlug 5 Prefs
You may not see all of those if you didn’t install some of the plug-ins.
Then try re-entering the keycode in one of the plug-ins, and it should work fine.