Samba config GUI doesn't show after entering password
Solution 1:
Should run Samba from Terminal.
$ gksu system-config-samba
If returns error message with last line similar to this:
SystemError: could not open configuration file '/etc/libuser.conf': No such file or directory
Create the missing file:
$ sudo touch /etc/libuser.conf
and run Samba again
$ gksu system-config-samba
Thanks Morbius1 for solution ubuntuforum.