Can't log in with 'admin' + services are down

Question

We can no longer log in to our server with the username 'admin'.. When we type in admin and the password, it just pauses for 10 seconds, and then shakes the login window as if the password was wrong.
Before this problem (on our intel Xserve, OS X Server 10.5.3) we used 'admin' + the password to use Screen Sharing and to log in to the File Server.
We used these services: File Server, Web Server, Mail Server, Printer Server.
Only the Web Service is working now, probably because it's not dependent on passwords etc.
After a Software Update (for Quicktime) and a re-start, we can't log in.
Using the name 'root' and the same password as the 'admin' let's us into the server, but this doesn't work for accessing the File Server.
When we log in as root, and start up Server Preferences, it says there are multiple errors, and there are no users in the Users options
The system.log is full of stuff like:
(org.openldap.slapd[1828]): Exited with exit code: 1
(org.amavis,amavisd[1829]): Exited with exit code: 1
How do we get things back to normal?

Answer 1

Pretty cool script here that will do what you're asking and more:
http://www.adx-consulting.com/en/downloads.html
You can use it or learn from it to write your own. You'll want to edit the files it installs as you see fit and change the password to the archive of course. The instructions are listed during the installation. Works fine on Leopard server. By default I believe it does weekly archives but you can change it to monthly or daily depending on your needs.