If I understand you correct from the movies, what you want to make is a character that have to jump off an object and grab hold of another one?

So the issue you have is really with animation and not the pivot point. If you start to change the pivot points orientation it will screw things up. As its the default rotation of the object, so what might be the default Y-axis for the character, could suddenly become a mixture of the Z and X axis. Which will make it near impossible to maintain control and is most likely why your character is spinning around like that. You shouldn't change the pivot point in order to make an animation, maybe if you are very good at it, it might be something to do, but im pretty sure that even they will avoid it and most likely rely on dummy objects instead. But that is just a guess.

Animation and especially character animation is very difficult in general, so that your animation goes wrong is very common :D

I don't know how much you know about animation and im not an expert my self, so I would suggest looking up as much information you can about it, both 2D and 3D. But basically how you can approach animation is to think about key positions or keyframes. Which are the limits of an object during an animation or what to say. Everything between these are inbetweens, which are basically frames that are the transition from one keyframe to another. Here is a simply example.

Lets imagine the ball is a character performing a jump. So you have a starting frame where he is standing on the ground, this will be your first keyframe, another where he is in the air and last where he lands on the ground.

So if you start by making each keyframe and make sure the timing is correct. Lets say it take 2 seconds for the character to jump, at 30 FPS it means you will need 60 frames. And to keep it simple, you can make the first keyframe at frame 1, second at frame 30 and the last at frame 60.

Once you have done that, you have a very rough animation, which obviously looks both bad and wrong, as Poser automatically make all the inbetweens. So this is where you have to fine tune the animation so it actually looks correct. So something like this:

So in this case the one called Anticipation, Jump (Contact) is added between the two first keyframes.and Fall (Contact) and Recovery between the second and third keyframe.

By simply adding these 4 extra keys, will make the animation look a lot better, as Poser can now make better inbetweens using these 4 keys as well.

But again I strongly suggest that you look up as much information about animation as possible, it is really difficult and it can easily go wrong....(Usually do for me :D)