Movie Files Don't Play
 

I've been using Limewire now for a long time and have never had a problem until very recently. When I download video files, 99% of them will not play. Some try to search for a licence and others give me this error message:

"Windows Media Player encountered an unknown error. This can occur when another program or operating system component encounters a problem but does not communicate the nature of the problem to the Player."

Does anyone know why this would be happening all of a sudden?