Why not just create a new user and specify the home folder location in WGM?
Open up Workgroup Manager.
Connect to your server.
On the top left side of the workgroup manager window click on the globe right under the Server admin button.
If it errors something about not being able to see the network blah blah... Click okay.
Select your admin user (if you can see it)
If you can't see the admin user, create a new user.
Might as well reset the password now just to be sure...
Click on the "home" tab.
Select the /Users item in the list of locations on the right side.
Click on the groups tab at the top right next to the "home" tab.
Ensure that the user is a member of staff and administrators.
Try and log into the server with your rebuilt user.