Here is what you have to do:
1. Burn the the M4P's onto a CD.
2. When it has finished burning, enter that CD into your computer again.
3. Click on "Audio CD" under "source" on the left side of your screen in itunes.
4. Then right click on the track you want to convert to an MP3.
5. Select "convert to MP3"
6. Once it has finished converting, copy that file to somewhere else on your computer (ex. C/Documents and Settings/User/My Documents/My Music)
7. Copy it again from where you just pasted it, and paste it into your MP3 player.