[mobilenutz]

I've seen problems like this on Windows Mobile phones when the native media player tries to autodetect the available network bandwidth (and it doesn't work right giving a very low value) and/or the bandwidth setting in the media player is manually set too low. Then the player and server will negotiate to just audio.

My suggestion - from the media player (when playing something) go Menu -> Options ->Network.

Turn off "Detect Connection Speed"
Set the connection speed to something fast - 256Kbps or something, doesn't have to be true

Try to restart video

If that doesn't work, try turning off the UDP and going only with TCP

Hope this helps.