[AUCTeX] Problem with getting preview-latex to work

[Ion Mihai]

Hi, 

I get the following error message when I try to do 'preview-document' 
in Xemacs 21.4.19 and AucTeX 11.83 under Windows XP:

"Display geometry unavailable: Symbol's function definition is void:
display-pixel-width"

Also, when I try only 'preview-at-point' I get:

"Symbol'sfunciton definition is void: 
previous-single-char-property-change"

Could somebody please explain to me why does 
this happen and what to do about it ?
Did I skip some step in the installation ? 
(I just unpacked
auctex-11.83-pkg.tar.gz, which I fount at 
http://ftp.gnu.org/pub/gnu/auctex/, in
my xemacs-packages directory; 
in the manual it is mentioned something about
activating preview-latex by explicitely 
loading preview-latex.el, only that this
file doesn't exist at all...)

Thank you in advance for all your help!