Windows Media player (10.00) message: "A security upgrade reuires to play this file.."

Hello,

I have the latest version of Windows Media player (10). I never had any
problems view streaming video files .WMV format.
But I find that I can no view WebTV video in MTV website. I got the warning
in my Media player: "A security upgrade reuires to play this file.."
But I can play any .wmv video files on other websites.

Also, I've been notifiedI got the message: "You need to upgrade your Flash
Player."
I have NO Flash Player, and do not plan to install it. Why I need Flash
Player if I want watch video movies?

What is the problem?


.