I am having a similar issue. A subscriber was deleted from Unity (can't see from admin page and SQL) and the AD/Exch account remains. Now when I want to re-create a subscriber for this same account, I can't find it from the add subscriber search page. It seems the Unity attribute is still tied with the AD accounts.
I believe this is included in the Cisco Unity Tools Depot on the Unity server. The utility is called Remove Subscriber Properties. Check in the Diagnostic Tools. If not there, you can download from http://www.ciscounitytools.com. Note: This is ADSIEdit and you are editing user attributes. When you find the user, if you see the Bunnyhead icon, Cisco Unity attributes are still associated with that account. Right-click and select Remove. It will prompt for your OK to continue. Once this has been run, you should be able to readd/import the user into Unity. Also, I find it easier to locate the user in ADUC first, so that I know which container/OU to drill down to.
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.