I am currently having this issue. My set up is Outlook 2007 with service pack 2, running on Windows XP service pack 3, Zimbra connector is 6.0.5958.7. Zimbra server is 6.0.6_GA2332. Tried removing both office and connector but still no luck. I can see it fine in the web interface after granting permissions to the users. I add the calendar by going into File -> Open -> Other User's Mailbox. I see the calendar open but no items. PLEASE HELP.
Also I get a failed synchronizing when refreshing the send/receive.