Cisco 6509

I just bought a NW-HD1. I can say that I like it very much but I am having some problems with it and I have emailed sony and of course they do not respond. Maybe some one here can help. When you Tell the unit to shuffle the music it will shuffle about 10 songs and it will go back and keep on playing the first song it started with. (I hope this makes since). I sure its something that I am doing wrong and any help would be helpful. Thanks