The Dreaded A12E1

I am running OS X 10.8.4 and only have two Adobe products installed - Lightroom 4 and Brackets (Sprint 29). I do not have any Creative Cloud products installed.

I am repeatedly getiing the 'A12E1' error and have restarted multiple times. To be specific:

- in Activity Monitor, there is no AMUpdatesNotifier process running. Only a few processes starting with A and they seem to be generic Apple OS processes.

- going to ~/Library/Application Support/Adobe, I have trashed the OOBE directory. The only other dirs are Camera Raw and Lightroom

- going to /Library/Application Support/, there is no Adobe directory

- running the Creative Cloud Cleaner tool, with Creative Cloud & CS6 Products selected, there are no applications listed. With 'All' selected, Adobe Id Credentials is the only listing

- opening the CreativeCloudInstaller.dmg, and then double-clicking on the icon, I get a progress bar which about 3/4 thru, prompts me for my password and then shortly after, produces the Error A12E1 warning

- I have restarted the machine and enabled the root user. Logging in as the root user & trying to install, I get the Error A12E1 warning again (so it appears to be unrelated to permissions).

No idea what else to try so would welcome suggestions.