[Zope] no accounts in root user folder?

[Vangelis Mihalopoulos]

Hello,

I have a zope app in a folder and have an exUserFolder in there to 
authenticate the app's users. The app is working fine and i get 
authenticated by the exUserFolder and everything works. I tried to 
delete the single "admin" account (with Manager privileges) from the 
root standard user folder and the app breaks with:

Unauthorized: You are not allowed to access 'call_backend' in this context

where 'call_backend' is an External Method called by a Python Script. 
All objects in zope are owned by the "admin". Could this be causing the 
problem?

Thnx for any help,
Vangelis