I can't play an AVI movie on quick time player. Why?
Because the codec needed to play that specific AVI isn't installed and may not exist for Mac OS X. Try installing Perian.
it helpe opening one of the movies, but not another one. Is there another program that might work?
Try opening it in the free MPEG Streamclip; this may reveal what, if anything, is needed to play it on Mac OS X.
If you cant play it in QuickTime, then another media player may be more successful. A couple of good options that generally pick up where QuickTime falls short are VLC (http://www.videolan.org/vlc/index.html) and MPlayer OS X Extended (http://www.mplayerosx.ch).
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