Cross DJ headphones problme with Numark iDJ3 controller

Hi there,
Just recently i purchase a Numark idj3 mixer controller, and decided to purchase Cross DJ software to use it. After installation of software everything seems to be working fine, but i cant get any sound when i plug in my headphones into my idj3 mixer. I need help please!!!!! Thank you.
Oscar.
Just recently i purchase a Numark idj3 mixer controller, and decided to purchase Cross DJ software to use it. After installation of software everything seems to be working fine, but i cant get any sound when i plug in my headphones into my idj3 mixer. I need help please!!!!! Thank you.
Oscar.