Is anyone able to Stream Video to MP11 from Win2K Server??

Folks....I have a Window 2000 Server (fully patched) running IIS and Window
Media Server. I am accessing audio and video content from a website using
ASX files pointing to my media server content.

Streaming these files seems to be working just fine for XP and Win98.
However for Vista users and those who have upgraded to MP11 it fails.

Can anyone offer an explaination and some help?

Thanks....RDK