My users cannot play videos from different websites, this is regardless of whether the video is Windows Media or Real. The sites are not blocked, but when the page comes up, the place on the page where the video should play is just showing a black box.
I tried one of these links from the Proxy PC, and it works just fine. I went to another machine (behind the proxy) and tried, but I had to install Real Player. As RP is trying to download, a box pops up intermittently saying the internet connection has been interrupted, and download will resume when the connection is restored. In a moment, the box disappears. The RP download never completes. I see the connection attempt on the proxy activity screen.
This seems like a strange mix of symptoms. What could be causing PC's behind the proxy to not allow video, and for this system to not allow downloads? Everything else seems to work normally (email, internet browsing, etc.).