The new Crucial RAM (2x512 MB SO-DIMM) fixed the hangs on Repair Permissions. The hard disk is fine.

Adobe has updated the help page for the Flash 9 installation failing on OS X, [link|http://kb.adobe.com/selfservice/viewContent.do?externalId=4aa64290&sliceId=1|here]. The problem is that the Flash installer searches the disk for every copy of Firefox, Mozilla and Netscape. If it finds any old copies that were installed by a different user (e.g. a backup from a previous installation on another machine), it'll complain about "Creating file: 1008:5, -5000 Access Denied Error". Unless you are willing to chmod 775 on all the relevant directories, or delete all the old installations, the install will continue to fail.

The machine had several copies of Mozilla and at least one old copy of Netscape. I haven't finished cleaning it all up yet, but that should resolve the problem.

Of course, Adobe's installer's smart enough to find the other installations and smart enough to know the permissions are wrong, and smart enough to require sudo for installation, but isn't smart enough to set and reset the permissions (with an "Ok?" dialog) automatically. Grrr.

Hope this helps someone else out there.

Cheers,
Scott.
(The next adventure will be replacing the 4200 rpm 30 GB hard drive with a 7200 rpm 100 GB drive... [edit:] The only thing to remember when using CarbonCopyCloner is to use the same Volume name for the cloned drive. After that, it's all good.)