Q: Lion OSX Server password/Admin problems

hi all.

I've posted on a load of current threads trying to find stuff out to my real beatch of a problem... See below... (i have a new Mac Mini Server + Lion).

So for about a week i've not been able to log into the Lion OSX server.app. Every time i tried to log into it, it reacted as if i've entered the wrong password. At this point i could only assume i had forgotten the password so i found out how to reset passwords through 'CMD+R' and using terminal. This worked the first time when i logged into server.app, i had the usual 3 profile users PLUS a hundred or so other users that looked like file names. So, i removed these users and carried on. I set up the shared files again (as i used it for the other macs in the house to store documents) and all was well.

I went to log in again on thursday and it did the same - incorrect password. So i reset the password again. This didn't work this time for some reason. I can only assume i chose the wrong keychains option when rebooting from the password change. After searching the forums i couldn't find any useful info so i reinstalled OSX Lion. In theory, i would have a clean OS and new passwords. Once the install had complete, I Logged into the unit as normal but hen i tried to log into server.app i now get a message:

A right pain in the ****! Just to be clear, i'm running v.10.7.2. So i try to run Software Update because iTunes now doesnt work.. I get the error '.libraby.itl cannot be read as it was created by a different version of iTunes. Download the newer version?'

The software Update box comes up with a strange instruction:

So i add my (what i think is my..) Admin name and password but its not recognised. But isn't this the password i've just reset by CMD+R and the fresh install? So now i can't log into Server.app, or make any software updates. I have gone into accounts and checked the permissions there, but i can't change anything because the passwords i'm using aren't being recognised.

I have spent today searching the forums for some other advice and it seems there are a few examples of people unable to log into server.app. The fix that was suggested for these examples hasn't worked for me. This is the fix...

http://support.apple.com/kb/TS3960

When i try to do anything in terminal i get 'David is not in the Sudoers list. This incident will be reported.'

Someone has just told me to run the update from root using -

$ su root

and run the commands as root.

sh-3.2# launchctl load -w /System/Library/LaunchDaemons/com.apple.servermgrd.plist

However, when i enter -

"$ su root"

It asks me for a password. I enter what i think is my admin password, but i get:

"su: Sorry"

So i then downloaded the Server apps update directly from the Apple website - http://support.apple.com/kb/DL1488. I try to install it but get the below error:

Ok, so i then download OSX Lion 10.7.3 direct from Apple - http://support.apple.com/kb/DL1484 (I don't actually know if this is the right piece of kit) and try to install it... I get the same error:

So i got nowhere.

I get the impression that my permissions are screwed up and i have no idea how to fix it. I am 2 hours away from an Apple store so cant take it to the genuis bar...

Can anyone please offer any other methods of fixing this?