VLC Player not for old downladed videos just for new downloaded

Hello,

I have just tryed to open a video in VLC Player and VLC player plays the following message not for old downladed videos just for new downloaded videos:

You need WebXvid to watch this video. Free download avalible at:

When I go onto the site it does not make any sense on what to do!

Why is this happening? Can anyone advise on what I need to do?

Thanks