What kit is it exactly, Nokia, Sony, Parrot, or something else? Include the model number so we can download the manual and check what the mute line does.

Also, I think it would be best if you used JEmplode, or Emplode with these instructions to access the config.ini on the player. Save that to a text file and attach it to your reply. This way we can ask you to try specific things.

It will work!