Have you done su to root and typed
at a terminal prompt? I don't think xsane will find your scanner if sane-find-scanner can't find it. If the scanner is found, note how it is seen as /dev. You may have to change permissions for the device in /dev so that your account (or the users group) can access the scanner. I've run into that issue every time with one of my scanners. Once you change the permissions (if needed), try xsane again as user.