Hi, besides a Security Issue you have a conflict. Please remove your Flash 20.0 r0 & Flash 29.0 r0 : https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html then please reinstall : Flash Player Version: 30.0.0.113 Current Version https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, . . . .) Note: Other software is offered in the download. <Windows Only> As for your FVD I suggest you check the Developers Support Site : https://addons.mozilla.org/en-US/firefox/addon/flash-video-downloader/ which will find off of here where you installed it from. The Developer last updated it 2 mos ago so it maybe it is being worked on now. Please let us know if this solved your issue or if need further assistance.