Too much info for question above
What software did you use to copy the mp3 files to your cd-rw?
Your model states:
Aux Input for MP3, digital audio, and personal CD players.
That says it can play mp3 through Auxiliary input
It does not say that the cd player in the boombox can play mp3
-But it does say
Plays CD, CD-R, CD-RW
But this means that the cd-rw discs still have to be in .cda format
So, you would need to convert the .mp3 files to .cda format and then copy the .cda files to your cd-rw and then you should be able to play in the player itself
What you can do to convert your mp3 files to cda format:
(Do not know if it is free or not)
How do I convert MP3 to CDA? | CD Burning, DVD Burn