Based on your description, it sounds like you're doing everything correctly from within the film viewer. Your "uncompressed" choice might be encoding the avi file in a format that demands a codec that hasn't been installed in your Windows Media Player. You might try downloading additional codecs for Windows Media Player, or you might try saving the avi file from within film viewer with a different compression (codec) choice. I've had similar problems before, but I've always been able to work thru them by diddling with those variables.
Of course.... some codecs are better than others. Experiment and find the best one that works for you.
-Peabody-