WMP11 Streaming to xbox 360

I've recently connected my xbox 360 to my computer's wireless network. For
about two months I was able to stream music, Divx files and anything else to
my xbox 360 through WMP11 with no problems. For the last three months
everytime I have attempted to stream divx files or any other video file my
WMP11 will suddenly disable media sharing and report an error. This doesn't
happen with audio files. I need to then access my WMP11 and re-enable media
sharing for the streaming to work. This happens each time I try to stream a
video file. Any ideas on how to fix this?
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CZ