Audio Systems: CD Compatibility, portable cd player, alpine system

Question
I burned a CD from a cassette for someone locally, using a computer DVD/CD burner (LiteOn brand).  I used Nero software, and selected "audio" CD.  He got an "error" on a DVD/CD machine, and the CD skipped or sometimes didn't play to the end on portable machines.  On my computer player and the burner, as well as a newer portable CD player, it played perfectly.  On an older (11-12 year) portable
CD, it wouldn't play.  Are CD's coded differently now, or is there something else going on?  I am not sure of the age of his machines.  THANKS!

Answer
it's got something to do with the coding, and the quality of the 'pits' that are burned, most older machines, even the alpine system i put in only 3 years ago won't read them without skipping. your 'newer' player is set up to read them. this should be illegal, in my books, making people get rid of expensive equipment every few years just so they can make billions more.....