windows media player cannot watch online content

recently my windows media player fails to play online video such as movie trailers or online tv, the error message says

"windows media player cannot play the file because the specific protocol is not supported, if you typed the URL in the open URL dialog box, try using a different transport protocol such as http or rtsp"

I am not sure what kind of error this is, while the media player works fine with all offline media files.

thanks

maybe your missing a codec or two
full codec pack available at http://www.filesharingtalk.com/vb3/s...ad.php?t=81899

problem solved with your help, thank you