In order to fix the problem, I recommend that you update Free Download Manager to the latest version. Browse the official web page, click the Download button, save the file to your computer and install it following the on-screen instructions. After that, reboot the PC, enable the plugin, access the YouTube page, right-click anywhere you want and select Download video with Free Download Manager. After that, select a destination directory, enter a name for the file and click OK. If you still have problems, you can try using another utility from Software Informer database, specially designed to download videos from YouTube.