If your file IS divx/xvid...
Xvid/Divx are output files, not meant to be edited (variations of the MPEG4 codec, often used for Internet streaming video) so, they mostly do NOT edit well (if at all) in any flavor of Premiere, even if wrapped inside an AVI container
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To edit a divx/xvid file, or convert to a format that will edit in Premiere
-start at http://www.divx.com/ or at http://www.xvid.org/