737 professional eratic & jumpy controls

I recently got the 737 professional from just flight but when I load it the controls (yoke and rudder pedals) are very jumpy and don't respond as it should so the plane is not flyable. I have contacted their support and they were very helpful but unfortunately could not find a solution. All my default and other add on planes work perfectly fine including other planes from just flight like the C-130 and 757. I have fsx with acceleration, windows 7 64 bit, saitek yoke + saitek cessna rudder pedals with 2 throttle quads and the saitek switch panels. Has anyone else experienced something similar or maybe know why only this plane acts this way? They've offered to exchange it for another product but I would really like to use this as I'm a big fan of the 737-200.