It sounds as though your mp3 player is not up to date with the latest tag versions. Some mp3 players lag a bit behind in that regard. If it's not that, then it's definitely a codec issue meaning your app does not have the ability to play this particular file. Update your app!! You haven't said what type of app you're using so the best I can do is : I don't know if this will be of any help but see: http://www.gnutellaforums.com/showth...threadid=25989
http://nimo.titanesk.com
Maybe you don't have the right codecs. Get GSpot (a free program) that will identify the codec that you might need .. it's free and it will tell you what you need to play a certain file.. just open the file in GSpot and it will tell you.
http://www.headbands.com/gspot/
http://www.gnutellaforums.com/showth...threadid=26644

I hope one of these links help to solve your problem!