Completely wipe OD master data?

I've been trying to promote my 10.5.7 server from standalone to OD master. I've done this many times successfully on Leo server, but this one is stuck. Forward and reverse DNS are correct, and "changeip -checkhostname" is saying hostnames match. But when I use server admin to do the promotion, I click the final 'Continue' button, and the gearwheel spins and spins for about 5-10 mins, and then throws this error: "The server reported the error: 'kNetworkError' while processing a command of type: 'writeSettings.' I've deleted the /Library/Preferences/DirectoryService folder, removed all LDAP entries from Directory Util, and rebooted and tried again, but I get the same error each time. Can someone tell me how to remove ALL Open Directory related files, so there's nothing leftover from one of my failed attempts, and so that I can start over from scratch, and do the promotion from a pristine state? Thanks!