This can happen if you have performed a complete backup (mirror image) of the system drive and leave the backup disk mounted on the Desktop when attempting to reauthorize the software.The DeAuthorizer from the diskettes seems to get confused when it finds duplicate files. One on the newly installed Mac OS and a copy of the same system software, plug-ins and applications on the backup medium which mounted on restart.Workaround: Unmount the drive (or disk) from your system which contains the backup of your system.