system-config-samba.py crashed with RuntimeError in readSmbPasswords(): You do not have permission to execute /usr/bin/pdbedit.

 The message "You do not have permission to execute /usr/bin/pdbedit." is wrong
I can execute that /usr/bin/pdbedit, actually everybody can.
-rwxr-xr-x 1 root root 2.0M Mar 17 15:44 /usr/bin/pdbedit

As of Xubuntu 12.04, the problem is in /usr/share/system-config-samba/sambaUserData.py 53-78
The script should have returned the actual status, stderr, stdout from /usr/bin/pdbedit, which would be helpful in debugging, instead of generalizing unknown cases to a specific error message.

Running the command manually for me returns:
-------------------------------------------------------------------------------------------
+ sudo /usr/bin/pdbedit -L -w ; echo $?
Can't load /etc/samba/smb.conf - run testparm to debug it
1
-------------------------------------------------------------------------------------------
+ testparm
Load smb config files from /etc/samba/smb.conf
rlimit_max: increasing rlimit_max (1024) to minimum Windows limit (16384)
params.c:OpenConfFile() - Unable to open configuration file "/etc/samba/smb.conf":
        No such file or directory
Error loading services.
-------------------------------------------------------------------------------------------

...which brings up the next question: why reinstalling "samba" did not recreate the "/etc/samba/" , but at least it is clear what's the next problem to deal with.

xubuntu 15.10
---
metin@metin-xubuntu:~$ sudo system-config-samba
Traceback (most recent call last):
  File "/usr/sbin/system-config-samba", line 45, in <module>
    mainWindow.MainWindow(debug_flag)
  File "/usr/share/system-config-samba/mainWindow.py", line 116, in __init__
    self.samba_user_data = sambaUserData.SambaUserData(self)
  File "/usr/share/system-config-samba/sambaUserData.py", line 46, in __init__
    self.readSmbPasswords()
  File "/usr/share/system-config-samba/sambaUserData.py", line 63, in readSmbPasswords
    raise RuntimeError, (_("You do not have permission to execute %s." % pdbeditcmd))
RuntimeError: You do not have permission to execute /usr/bin/pdbedit.

recently started happening in Mythbuntu 14.04

Found smb.conf had an invalid security setting "security = share". I know I had changed it, but I didn't comment why. Setting "security = user" and adding "map to guest = Bad User" allowed system-config-samba to launch normally.

More info here: http://ubuntuforums.org/showthread.php?t=1962617