Traktor Pro2 and S2 problem

Hello,

I bought S2 2 days ago. I followed the setup manual while installing Traktor and setting up S2. When I open Traktor the CPU indicator above is swinging between blue and red and when I connect S2 the exclamation mark on it blinks. Songs sizzle or stuck for a second. I take the output to a 2+1 pc speaker system.

My laptop -> Dual Core i5 2.3GHz, 4gb ram.

What could be the problem because it doesn't seem working properly to me :)

Thanks for your help