You're just trying to copy the dialer images for editing?
Which dialer are you using? I have all the default images for the Touch Dialer in my ftp in the "themes" folder.. also there's the default "crossbow" dialer images there too.
On vista too the \Windows folder doesn't show up in explorer. It used to for me, but I'm guessing it was an update to WMDC or something that killed it. Most people can't see \Windows from Vista though. Could try copying to storage card or another folder first using the file explorer on the PPC and then browsing to that folder on your PC. Not sure exactly what kind of prob you're having.
Touch Dial stock images
Crossbow Stock images