I just tried to install the «Zen-Coding» extension for DreamWeaver CS4 (http://www.adobe.com/cfusion/exchange/index.cfm?event=extensionDetail& extid=1965527) on a Mac G5 PPC running OS X 10.5.8. All I get after accepting the TOC in Extension Manager is a message that the extension won't be installed because the menus cannot be updated.
Other extensions like e.g. http://code.google.com/p/chrismckee-project-bay/wiki/HTML5Weaver install without a hitch.
Any help is gratefully appreciated, thank you!