Media Sharing with Windows Media

I was trying out Media Sharing using Windows Media Player between two Windows Vista machine. The desktop OS is Vista Ultimate and the laptop is Vista Business. So far the setting seems to work pretty nice with audio, but I couldn't make video to work. I think mostly because the WiFi connection is kind of slow. But then opening media file directly using KMPlayer thru network seems to work pretty OK. So ... I am pretty clueless.