I checked your link and got the same message. However with the aid of Mr. Google I found this link which works for me. You can click on the floppy disk icon in the upper left corner to save it.
It must be something PPC related as I just now downloaded with a MacBookPro and it works perfectly. Then I tried with my PB G4 12" and it would not load at all.
I may have found something on a site called Manual Owl. There are two PB G4 1.67 manuals that easily come up on my G4 screen. I can't download or save them to desktop though, butthere is a option to print however.
Check them out here.