Here's how I got Photoshop Elements 3 to run as a non-admin user. This assumes your short user name is me, and your admin user's short user name is admin_user. Open Terminal, and type the following (don't enter the $; that's the prompt character):
$ su admin_user Password: Enter your admin_user password $ sudo chown -R me.me /Applications/Adobe Photoshop Elements 3 Password: Enter your admin_user password $ sudo chown -R me.me /Library/Application Support/Adobe/PhotoshopElementsHelp $ exitPS Elements 3 will now run quite normally as a non-admin user...

