I’m posting this in the hope that I can prevent someone else from losing their mind. The shiny new Adobe Creative Suite ran fine on my G5, but when I tried to install and run it on my G4 Powerbook, the dock icon would bounce for a few seconds then quit. I tried a variety of fixes - re-installation, trashing preference files, repairing permissions, installing under a different log-in. I even rebuilt the Powerbook from scratch in case that might help. Still no cigar.
Finally, after having a Damascus Road experience on a MacUser forum, I found the fix, and you’ll never guess what it is. Go into Date & Time>Time Zone and change the setting from ‘GMT’ to ‘London’ (or anything other than GMT). Suddenly, everything opens and works fine.