Strange message at start

[Nick]

At start as root or as user I see error window with message:

"Sorry, this should not have happened

An uncaught error occurred. Close this message window and restart the application.

Please report this error on https://bugs.launchpad.net/sbackup.

coercing to Unicode: need string or buffer, NoneType found

Traceback (most recent call last):
  File "/usr/share/sbackup/sbackup/ui/configgui.py", line 1103, in on_dest1_toggled
    self.on_dest_localpath_selection_changed()
  File "/usr/share/sbackup/sbackup/ui/configgui.py", line 1542, in on_dest_localpath_selection_changed
    if (os.path.isdir(_target) and os.access(_target, os.R_OK | os.W_OK | os.X_OK)):
  File "/usr/lib/python2.7/genericpath.py", line 41, in isdir
    st = os.stat(s)
TypeError: coercing to Unicode: need string or buffer, NoneType found"

after close this window appear same window and then program start OK.

Xubuntu 13.04-64
UTF-8
SBackup 0.11.4