Trying to use the classic template on a fresh 1.4.8 install, logging in 
as "admin" user and select Administration-"Add User" from the menu. 
After filling in all required fields and pressing "Submit new entry", 
nothing happens.

Looking at the source-code in cgi/actions.py NewItemAction.handle 
appears to specifically block user creation:

        # guard against new user creation that would bypass security 
checks
        for key in props:
            if 'user' in key:
                return

I think this is a breakage from 1.4.6.