Help needed unmanaging the Local 10.6.2 client admin user

Hi. I have a local user on all my client machines called admin with admin rights. Have had this same user with same password for many years for our machines. over 300 client machines from emacs to intel macs. With the 10.6.3 server update (major issues for the last 2 months) with 10.6.2. intel imac clients, logging in as admin gives me a reduced dock. just finder and trash. Every use of any applications comes up with "you dont have permission to use the application "xyz". with 3 buttons Always Allow, Allow once and OK. entering admin and password always results in a second box with the same message. entering admin and password then allows me to use it. This behaviour does not happen on 10.5.8 clients and has never happened before.
In system preferences it says administrator, admin is managed. clicking the lock and authenticating allows me to access the tick for Enable parental controls. If I click on the tick to remove it, it comes up with the message. "You cannot enable parental controls for an adminstrator account. Create a new user account etc." It is unticked but the tick comes back on restarting the system preferences and even restarting the computer immediately.
I have tried deleting managed prefs etc but to no avail. I have tried removing the computer from the network account server and I get my dock back and can use applications but it still says I am a managed user. and I need the network account server for student logins. Any thoughts how to unmanaged local admin users on client machines to get back to the way it has been since 10.2.4 clients!!!