Just in case it wasn't clear, I've modified the Kinect rig to plant it's feet on ground level. If you are using an IK rig, just make sure your IK handle bone is in the same position as the Kinect feet bone. If you're using FK instead, then you're just getting rotation data so it shouldn't affect you. Also, DO NOT change the roll of any of the Kinect bones!!! You can move them, but if you change the roll, you destroy the original animation data-! Hope that helps :)