I found the flash fallback is not working. I have only one video file, an MP4 file. It played on IE, Chrome, and Safari, but not on Firefox. I replaced the MP4 file with a FLV file and it played on all four browsers, including Firefox. I checked the following suggestion at videojs.com to add another line after the video end tag. I did not see such a line after the video end tag in the videojs.tpl.php module. Would this be causing it or am I doing something wrong?