It seems your an NE customer/In a previous thread you wrote: "I installed Zimbra Network Edition 4.5.6 on Ubuntu 6.10 this weekend..."
Be advised there is no support (except the forums) for this:
-Go to
Zimbra Support Portal - Home & login
-Under "Support Menu" on the left hand side
-"Pre-release downloads"
-"Connector for Outlook (ZCO)"
Right now that's ZimbraOlkConnector-4.5.7_GA_1140_4.5.324