I think that glitch might be a client-side issue, especially if it is happening repeatedly to the same people. If you find the pattern is more random let me know. Also let me know if you find this happens more often when the server is full or anything like that.
The media player used in your version is heavily dependent on what te client has installed on their system for activex media playback. It can vary. It might help to male sure they all have the latest version of windows media player.
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