You didn't do anything wrong; it's just that CD players can't play DVDs. If you put the music on blank CD media (not CD-ROM), you'll be able to play them on any CD player.
...but not on any of the hi-fi? in the house. What have I done wrong? Was I supposed to do something like format the disk especially for music or what did I do wrong that it plays on my laptop but not any cd players in the house?