Xemacs and lilypond

[Eddy]

Hi ! 
 
After reading the archive of this list, I created a file init.el,  
and I wrote these lines in it : 
 
;;; lilypond-init.el --- Startup code for LilyPond mode 
(autoload 'LilyPond-mode "lilypond-mode") 
(setq auto-mode-alist 
(cons '("\\.ly$" . LilyPond-mode) auto-mode-alist)) 
(add-hook 'LilyPond-mode-hook (lambda () (turn-on-font-lock))) 
 
When opening a *.ly file with Xemacs, I have a message in the mini-buffer :  
 
File mode specification error: (file-error "Cannot open load file" 
"lilypond-mode") 
 
Where can I find the file "lilypond-mode" for my version of lilypond ?  
How do I know which version of lilypond I have ?  
Where do I put the "lilypond-mode" file ? 
 
(I use lilypond and Xemacs for windows, xp). 
 
Thanks