Reply to Vci 100 fader and slider problems traktor pro

Can anyone help. I'm mapping my VCI 100 to traktor pro and i'm having problems with the faders and sliders.Once i have mapped them, the sliders don't work smoothly they jump around. the crossfader will not go to either side and just sits in the middle. if i map a knob to any of the volume controls this seems to work fine. Any ideas would be great.