Like some other people, I followed your steps, but I kept getting a "TWAIN source unavailable" error (the wording might be slightly different).
I uninstalled and re-installed the LiDE 60 driver
several times, tried the CanoScan Toolbox versions 4.9 and 4.5 multiple times, all to no avail. I tried to use VueScan instead, because it supposedly fixes scanner compatibility issues. Did not work.
What finally did the trick was this additional step:
I used the File -> Import menu in Photoshop CS3. This listed CanoScan LiDE 60 as an option. This started a Scangear CS menu, which in turn automatically started a callibration of the scanner. I then successfully used the Scangear CS menu to make my first scan with the LiDE 35 scanner!
When this was done, the CanoScan Toolbox 4.9 also recognized the scanner and worked normally.
Hopefully this trick will help other people that have trouble getting the scanner to work. Maybe there is a way to run the Scangear CS program without Photoshop, because I think it's part of the Canon driver. If so, people without Photoshop can try that.