Wadia iTransport problem

I've just received my iTransport yesterday and got it connected. When I put it on the digital output mode with a DAC. There is a "click-Clack, click-clack" sound every time when I pressed the "STOP" or the "FORWARD NEXT" button. The noise level is quite high. I'm afraid it might demage the speakers. I also tried it on another DAC with another amplifier system. Same thing happened. Anyone have this problem ?