Just a heads up. If any of your clients have a user that complains that they can’t access public folders, they may be having a problem with a recent client-side Outlook 2007 security update. If they attempt to access public folders and are getting this error:
Cannot expand the folder. The attempt to log on to Microsoft Exchange has failed
It’s likely that they recently installed KB980376. As of today, the only known fix is to uninstall that security update from the client machine so that they can get into public folders.