NEVER render an animation as an AVI; that can ONLY lead to grief.  In your animation settings, set to render as individual tif frames instead, to be saved in a special folder.  Then afterwards, assemble them into a movie in  Animation Shop or Gif animator, or some such program.  That way, you'll avoid whatever codec problems, and increase your control over the output.  (Also, if for anyreason the render should stall in mid process, you haven't lost all your work
DPH

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