Also make sure you don't have the object aligned with path in the attributes box, in Bryce 4 and 4.1 there is a bug that was never fixed where the object spins weirdly towards the end of the path, that's fixed by simply by adjusting the axis of the object and where you want it positioned,and re-applying that last keyframe.

Do atleast one thing a day that scares the hell outta ya!!