very strange problem with moving objects

I am stuck with a weird blender problem now, I have no idea what is going on.

I have a simple scene with a few spheres and a plane as ground. When I move the spheres’ locations, save the file, and immediately reload, they are all stacked on one another (occupying the same space). If I restart blender it doesn’t help. Can anyone explain to me what is happening?

I tried doing ‘Load Factory Settings’ and redoing the scene but it seems to have happened again (It seemed to happen sometime around when I did an Undo so that may be related)

Here is my (extremely simple) file:

Your spheres have all the same IPO datablock that defines, among other things their location: same ipo = same location, for every frame, all the time.
You can move your sphere around in the 3D view but if you don’t set a key the location defined by the IPO datablock will have precedence. Just try to change frame and see.

Thanks IAmInnocent! My next question is how do two objects end up sharing a IPO datablock and how do I get them separated?

I have been using blending for several weeks now, I don’t know why I haven’t had this problem before…

Select one object and click the X next to the IPO name. That breaks the link between that object and the IPO Curve. The number of users indicator should drop back to 1.

There’s a couple of ways this can happen but my guess is that you created one sphere and, for some reason, gave it an IPO. Then you made four copies of it using Shift+D. One would expect that copies are completely independant in every aspects while instances would share every datablock above the object datablock level… Well with Blender this will be the case only if you set it like that in the Preferences > Edit Methods > Duplicate with Object. By default the material(s), texture(s) and IPO(s) are not duplicated but are shared among
all copies.

I have been using blending for several weeks now, I don’t know why I haven’t had this problem before…

Stuff happens. Maybe you played with the original sphere at some moment, forgot about it then picked it up again. Maybe you have autokeyframe active (same place in the Preferences). Maybe you did hit the Ikey by accident and dismissed it with a LMB not far enough or even an ‘Enter’ reflex. Who really knows how stuff happens?
Hopefully at least you are having fun,