Hi FramerX I replied to your PM with a suggestion and a couple clarifying questions. Let's continue the chat here so others can benefit.
Here is a suggestion. Try putting an led before the mp3 player, so you know when it is getting a signal. Even better than an led would be a bargraph or number Bit, because they would give you more information.
A couple questions for you:
1) What is the other wireless circuit?
2) How long are the files on the mp3 player?