Cannot upgrade from Connector 6.0.5797.4

[mattcen]

Hi all,

I've got a client currently running Outlook 2007 (12.0.6539.5000) SP2 MSO (12.0.6545.5004), with Zimbra Outlook Connector 6.0.5797.4, and am trying to upgrade to 6.0.5981.7, and it's not working.

Despite Outlook apparently connecting with Zimbra, I can not find evidence of Zimbra Connector in Outlook. For example, I'd expect to be able to go to Help -> About Zimbra Connector, but it's not there. If I try to install the new version, the progress bar gets partway through before rolling back and saying

The installer was interrupted before ZCS Connector for Outlook could not be installed. You need to restart the installer to try again.Click "Close" to exit.

If I just try to uninstall the existing Connector, the progress bar cycles madly, before the Windows Instaler window closes without warning. It looks again like the uninstallation is rolling back before this happens.

Has anybody else seen this before, and found a solution to it?

Thanks in advance.