Tell us a bit more about the code is it just an MP3 player you want to embed?? are there any links to the actual product you can give so we can see at first hand??
I see [FLASH] is there but there are too many variables that need to be passed off for most MP3 players to work on a forum post???
Every little helps
Have you seen this hack?? Embed MP3 in post using flash player
https://vborg.vbsupport.ru/showthread.php?t=170794
Could this be what your looking for????