Can someone help me with this one, I am unable to taxi as the rudders and all control surfaces are fluttering all the time. I have recalibrated the joystick, and the joystick outputs are steady, I get this problem on and off line but only with the PIC 767. The only way to stop the controls flapping is to turn off all the hydraulics!! When in the air the a/c flies OK on autopilot, and doesnt appear to have any problems. I have had the PIC for a few months now and this has only just started to happen. My sytem is top spec and I am using a Saitek usb Joystick

You are not alone with that problem. Solutions range from version of FSUIPC to Yaw damper switches turned off. And, a lot of things in between, like sensitivities. For some, I think the problem has never completely gone away. Try searching this forum for "rudder" and again for "fluctuate" and have a look a some of the previous threads on this subject.