2008 Urban runner package - Need help with No sound from USB content

[redmond4runner]

All,

Joined recently as I bought this 2008 Urban runner sport edition.

Problem - has this head unit which has little nav and USB port. when I plug in USB, it detects the songs and starts playing them as well. (can see the progress bar for MP3 songs) but no sound !

Radio and CD works just fine

Any help?

thanks