Check out this link - http://www.cisco.com/en/US/docs/voice_ip_comm/unity/41/requirements/40_41cusysreq.html#wp33189, which contains this caveat "Microsoft ended support for Exchange 5.5 on December 31, 2005. To the extent possible, Cisco will continue to support Exchange 5.5 as a message store for a Cisco Unity system installed in 2005 or earlier. However, if a problem with Exchange 5.5 cannot be resolved, the customer will be required to upgrade to Exchange 2003 or Exchange 2000." The minimum Windows 2000 service 3 for Unity 4.0(3) shows as SP3, where as the minimum for Unity 4.0(4) shows Windows 2000 SP4 - posted earlier in the same link. I found a few hits on Google about issues with Windows 2000 SP4 and Exchange 5.5, after applying the roll-up, but nothing specific to Unity. Do you have a test system you can try this out on (recommended)? Have you thought of upgrading Unity and Exchange?
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.