After several attempts, I was able to get it installed. My previous post in this thread hasn't appeared for some reason.
Basically, I let the thing run two hours with the progress bar at the end. Then it would ask for ksuser.dll. Searching my C drive for it, I loaded from C:\WINDOWS\ServicePackFiles\i386, then the process finished. I also, based on other discussions here, removed the nameless mouse drivers before installing Tools, but I don't believe that had anything to do with it. See screenshots.
Good news is that now I have it upgraded, the system feels very 'light' and responsive, especially with Time Machine also running, as compared to PD5 where every ground to a halt with both running- even on a new core i7!
Good job Parallels!