nero 7. help

I just install nero 7. But can't get this thing to work. I tried to burn an mp3 player to a blank cd but can't get it to work. I already wasted 4 cds and still can't get it to work.. ..
What I did is:
1. make mp3 cd. Then it goes to nero express at which I add the playlists I wanted. And then, everything just next and next w/o any problem. It even states "burn succesful" But when I try it at my car stereo(of course it supports mp3), it just states "error"

does the mp3 cd work on any other player?? does it work in your pc
try this, uncheck "allow files to be added later (multisession disc)

p.s. you might find better help on a forum thats not designed around photography but good luck.