|AVI is just a container for video files that may be encoded with any one of a number of codecs. It's possible that the codec used on the video you tried to play isn't supported by the TV (perhaps some obscure, less-common codec).|
Try a few AVI files, from different sources. If any of them play, you've likely found the problem.
gSpot, (a freeware program, google it) can be used to determine which codecs are used on audio and video files.
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