> the scroll-preserve-screen-position variable had been
 > introduced some time ago in emacs 20. It allows to
 > keep the cursor in its position in a buffer when scrolling.
 > When it is not set, the cursor position is moved when
 > scrolling so as to make it always visible.
 > In emacs 21 (and alas in 22) this variable has no effect,
 > at least when emacs in running in Windows XP and also in
 > Vista.

Thank you for your report.

Customization for this variable was broken.  Could you please apply the
attached patch and tell me whether it gives good results.