This is one fix that I know works if users are experiencing Adobe Extension Manager launching crashes using Adobe CS5, Mac OS X 10.6.8. I've tried many of the suggested solutions offered here and the only one that seems to resolve it is to backup your particular user folder, create a new user account. Then login to that account and you'll now be able to launch Extension Manager normally. Don't forget to transfer over only your necessary data from your backed up user folder to your new user account (i.e. Desktop items, Pictures, Documents, Mail, Downloads, Music, Movies and DO NOT transfer over any Adobe caches, prefs, etc.
When you have this completed, delete your old account with the corrupt Extensions Manager components.