heya; the curve parameter sometimes causes parts to twist like this at certain angles. when working with my swan's neck and horse reins, i found that the twists often worked themselves out when the parts were positioned. if not, select the segment, and turn its curve dial to zero. you can also experiment with different settings for this dial. as for the sharp bending problem... um.. dont do that ;) mess with the curve dial, and also, make sure if you want to bend segments a lot, they have a lot of vertices for poser to work with.