Firefox : plugin not found

[Miso]

Hi,

I went to the demo page and selected this link :
http://altair.videolan.org/~dionoea/vlc ... height=240

I get a blank page with the usual logo asking if I want to get the plugin.

I click to get the plugin and get the message "plugin not found".

What could be done so that Firefox is able to get the VLC plugin automatically (I don't want the users to install the full VLC software by themselves) ?

Thanks in advance.