Problem playing burned cd's in music systems

Hello,
i have 134 mp3 songs recorded in my 700mb/80min CD-R which plays well in my PC but not in my DVD player or MUSIC SYSTEM,i burned it using NERO,the commecial MP3 CD's are also 700mb/80 min and contain 120+ songs and work fine in my music system but the one i have burnt doesn't why is it so another cd which i made has 60 songs recorded on it but my car player plays only the first 21 songs why