This is what we're running.
Zimbra Network Edition 6.0.1
Outlook 2003 sp3
Zimbra Outlook Connector 6
ACT! 2010 hotfix 4
CompanionLink DoubleLook 3 (This syncs ACT! to Outlook)
We're trying to get a 2-way calendar sync going between ACT! and Zimbra. The above configuration works fine at first, but then it will randomly fail. We will close all applications, and the outlook.exe process will hang until it's killed manually.

It seems like the Zimbra Outlook Connector and the DoubleLook software are fighting for resources when they happen to run at the same time. We had the same issues with ACT!'s built-in Calendar Copy function.

Does anyone have any experience getting ACT! data into Zimbra by any alternative means? Or is there a better way to configure our current setup?

Any help would be greatly appreciated.