When I add a "pose" for the cowboy in my world and then play the world, I receive an error on that particular step. What can I do so that I can alter his pose?
This is likely due to that you saved the pose to the cowboy's upperbody(or someother place. check if the pose is called cowboy._______.pose) and you tell the whole cowboy to do the pose. If not you can manually program each part's movement.