You may have issues using the Revision Pro application for the following reasons:
REQUIRED FLASH PLAYER VERSION IS NOT INSTALLED
Please visit the Adobe Flash Player Download Center and follow the instructions. After the installation completes, relaunch the application.
CORRUPT FLASH PLAYER INSTALLATION
On random occasions the Flash Player installation is corrupted. If you know you have the latest version of the Flash Player, but you can't view the Revision Pro application, you may have a corrupt Flash Player installation. Please visit How to uninstall the Adobe Flash Player plug-in and ActiveX control and follow the instructions. When you have successfully uninstalled Flash Player please reinstall Flash player using the instructions above.