add user to group script section of man smb.conf has example calling /usr/sbin/adduser %u %g which is according to the man adduser wrong. When I try it, it also refuses to work.
adduser is system-specific - I've added a note about this.
originally reported against one of the 3.0.0rc[1-4] releases.
Cleaning up non-production versions.
sorry for the same, cleaning up the database to prevent unecessary reopens of bugs.