I downloaded 1) the Twain driver, 2) the Toolbox 188.8.131.52, and 3) the recommended driver called deldrvwin. They drop into a "download" file where I then install. I have done this about three times.
During the installation of the Toolbox driver, I get a message from Program Compatibility Assistant that states "This program may not have installed correctly".
When I attempt to scan using the Canoscan Toolbox, I get a message "Specifies the program where the scanned image is transferred". I have no idea what this means.