is it the 1st time you try to play a file with AC3 audio ?
It's weird that bsplayer would crash with Intervideo's AC3 Decoder [though I didn't try it with build 500]
You could try another AC3 decoder, such as AC3filter
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EDIT
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sorry I was talking nonsense intervideo's ac3 decoder is of course iviaudio.ax, not ivivideo.ax...
What kind of file is it exactly that you try to play ?