Toolbars settings - changes are not remembered or save'able

Hi

In Acrobat 9 Pro Extended, 9.3.3 on Windows 7 64 Bit ->
When I change the toolbar "Page Display Toobar" to show anything else than the default, like "Two-Up" (which shows up in the toolbar and works fine), then leave acrobat and start it again, it is going back to the default choice.

I used the menu -> Tools -> More Tools to change it, no success.
I tried directly setting on the toolbar, right mouse menu, no success.
I tried changing the settings with and without locking the toolbars, no success.
Tried to find a flag or paramter in general settings, which explains this, no success.

Adobe knowledge base or product help does not provide any explanation.

Any idea/tipp would pre appreciated very much !!

Thanks
Christian