Reply to TRAKTOR SCRATCH calibration problem help??

Hi, I am having some problems with my Traktor scratch duo software.Sometimes When I hook it up with my turntables the song playing on deck A or B starts going backwards for a few seconds or sometimes it skips. Is this a calibration problem? The calibration usually looks bad and a bit messy... but when I try to calibrate it it always fails. I bought traktor aboit 5 months ago and it worked fine and till now. what else could it be?

Thank you