This indicates that the file just can not be played, at least not by your media player. Most commonly this is a corrupt file(all is lost) or an FLV file produced by a Flash recorder.
If its an FLV file ..
ii) Make sure Poodll is handling your audio and video files.
Move the Poodll filter higher in list of filters than the Multi media plugins filter in : site administration -> plugins -> filters -> manage filters
iii) Set Poodll to handle FLV files.
iv) Poodll should really be converting videos from FLV to MP4. Try making your settings look like this in the Poodll filter general settings