Ich glaube eher euch fehlt die Umfeld Erfahrung um daraus ein Urteil für die Allgemeinheit ableiten zu können. Ich mache das aus purer Erfahrung und einem sicheren Gefühl - auch wenn ich neuer MAC User bin.
Root brauchte ich wegen dem Umbenennen des UserKontos, was ich nach Apples Anleitung gemacht habe. Der Fehler mit dem Root ist aber bekannt.
Die Lösung sieht so aus:
Directory Utility is at /System/Library/CoreServices - on both Client on Server.
Open it up, via Finder - and then click on Directory Editor
Make sure you are viewing Users on /Local/Default and that you are authenticated as root. (It does this auto)
Select the "Administration Account"
On the right under AuthenticationAuthority should be two keys - one ShadowHash and one Kerboeros
Copy the value - on my client its ;ShadowHash;HASHLIST:<SALTED-SHA512>
Select the "System Administrator
Select the AuthenticationAuthority and click the add symbol to the right.
Paste the value you copied into the new key.
Once I did this I was able to use sudo passwd root to change the password, and tested it.
A word of warning here - what I did gets it working - but it may be the wrong key, or add in insecure auth-authorities, as there is a diff between Lion Upgraded and Lion clean from what I can across my two computers and as such your root account may not be as secure as apple intended it should be.