The you need to be upgrade the application to the latest version.

In order to update SuperMemo UX you need to launch the app as the administrator. Click the SuperMemo UX icon with right mouse button and select Run as administrator. The application will start. Then from the menu at the top of the screen select Tools / Check for updates. It should download the latest version and install the update. The application will be restarted and now it should work just fine.