You may be able to play around with SQL Server to try and get it to copy data to other datbase server using SQL DTS, OPENQUERY, M$ DTS.
But I would say no, you cant get CM work via a other database. Also Cisco would not support it,
Cisco uses M$ SQL SP which not may work in Oracle and you would need to change all the ASP code to link to Oracle (big pain). You would not be save any money doing this as you get Windows and SQL when you get Call Manager.
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.