I think youre problem is, your CDJ can not read your IPOD folding. If you turn on, show hide folders you see theres more on your ipod. To get music worked with your cdj:
+ Select in i-tunes, show as external drive.
+ Open the drive with windows explorer
+ make an new folder, called music
+ ut your music in that folder for your cdj
+ now open it as an external harddrive i your cdj400
i think there's no probelm anymore