Downloading with the nero express option

i was downloading songs from a site called jazz on line.i sent the songs to my
desk top then opened up the nero express window and dragged the songs in-
to it.some songs wont go into it as i get a prompt saying one or more songs
cant be added.maybe if you had a dedicated plug in you could add them…wh-
at is this dedicated plug in and where can i get it??is it a nero update??thanks