Key Frame Problems

I’m having some trouble with a scene I’m working on. I set up a few objects, set their parents and made a few track some empties. I key framed them to create an animation and when everything was how I wanted I duplicated the objects and rotated them to create the scene I wanted. First I found that I had to delete the tracking and the parenting and redo all of this for each object. However now when I add a keyframe to the scene and then change the current frame the objects move erratically. I can’t figure out why and it’s starting to really bug me. Here is the .blend file if you need to take a look at it:

http://www.telusplanet.net/demonghast/supertech0030.blend

I had started this little prjoect to learn more about animating things but this really has me confused.

You probably shouldn’t duplicate objects after they’ve been animated and parented, etc. The scene should be finished before you start animating, once you’ve finished building everything you can start parenting and then animating.

With shift-K in the 3d window you can let blender show and select all keys.
Now move/rotate your object(s) and this will effect the IPO.
Make sure you have 1 IPO per object (not a linked IPO).

I deleted all of the IPO values. Shift-K moved the objects back to some earlier point before they were duplicated. It would be impossible to move all of the objects back to their original points again.

All of the parents were removed and the tracking was removed as well so just the objects were duplicated. I’ve already stated this in the first post.

If I have to start over again that can be done but I’d still like to know why this has happened. Please take a look at the file if you can and let me know what I 'm doing wrong.