Entire Lesson won't Play in Ipod

[suying]

I have downloaded a few lessons entire audio files (i.e. Survival Phrases I,II and Beginner Lesson 1 to 6) and drag and drop them into my Ipod using ITunes7. However, when I read the notes and click on "Play Entire Lesson", it just won't play. I have to manually play the lesson file by accessing Music -> Song-> select the particular lesson audio file to play. Please show me how to rectify this problem. Thank you.