LW player is for music preview. If you want to preview a movie, your system should actually choose your default movie player (i.e. Windows Media Player, RealPlayer, etc.)
To avoid problems with missing codecs, you can also download the free VLC player wityh built-in codecs. When installed it will become your default player for all media files. It can play almost all files know.
http://www.videolan.org/vlc/ 