So everything seems to work out fine. How to scan images now?
If you don't have X11 installed (this is highly unlikely) or if
you just want to rely on the command line, you might try to use
the command scanimage with some appropriate parameters.
Far better is of course to start xscanimage unter X11 or
to use the gimp for scanning. If you have installed the
gimp and scanning with xscanimage works,
you can automatically access your scanner form the gimp
via the menu items Xtns and then Acquire Image and
then plustek:'' dev'' pt_drv. Or directly from
the File and Acquire menus. That might be the
best option, for it is not only convenient but you also have the
full image processing power of the gimp at your disposal.