I think the crux of the problem is in the way musicmatch 'tagged' your files. There is no standard for tagging wave files, like id3 tags for mp3 and ogg files. Rhythmbox should play your files fine, but has no idea on how to read the tags (Banshee should work, as it uses gstreamer to play the files, but it would have the same problem reading the tags).
In doing a quick search, this holds some promise:
Another way I found from a search of 'musicmatch wav tag' would be to use the MediaMonkey program in expee to convert all your tagged wav files to flac or ogg (or even mp3), thus guaranteeing their linux readability. Just doing a cursory look at the program, it looks like one of the few that can decode musicmatch's tags.