I think this is a different problem, but I will soon find out. I compared the iWorks installs on the Mac where the error was reported to the ones where it was not, and the packages sizes were smaller on the former -- so even though the applications are running on that Mac, something is missing. I tried to make a dmg file of the install DVD on the Mac where it did not install properly, but Disk Utility reported a failure at just about the same point (nearly done), so I made one on another Mac. I'm now copying it over. Personally, I think it might well be a bad DVD pressing.