I am having a hard time with Allvideos. I have tried local mp4 files, youtube, and to a degree dailymotion. I have Autoplay set to Off, and the plugin is activated.

With local mp4 files, I see a big white box inside a black border - no audio or video and the file is in the correct directory with the correct permissions.

With YouTube - same exact thing as with local mp4 files.

With Dailymotion - I can see the initial image with a play button. Upon clicking the play button, same white box with a black border.

This occurs on both Chrome and Firefox. Each time was done on a clear cache, both in the browser as well as in Joomla. I have also tried disabling Joomla's cache to make sure that was not it. Any idea's? I used Allvideo's in the past with earlier versions of Joomla and it worked great. Are there any known conflicts between other modules or components for Joomla?

On a side note, going to youtube, or dailymotion ... the video plays fine from their site. The mp4 file also plays fine in VLC and Windows Media Player.
Joomla - 2.5.6
Allvideos - 4.4
PHP - 5.4.4

Well, figured out the solution to the "white box".

The problem is with "Shockwave Flash", more specifically the plugin it installs for Firefox. Disabling that plugin, in Firefox, fixed the issue for Firefox and Chrome.

This issue is from a clean install of shockwave flash 11.3, so here is a heads up on a compatability issue. Also, for some reason it seems like everything including flash works just fine with that plugin disabled.