Comment 15 for bug 477309

Fresh install of Karmic using the 195 driver also repeats the earlier symptom of not being able to save the xorg.conf file. Running gksudo /usr/bin/nvidia-settings lists a few lines that may help:

/etc/X11$ gksudo nvidia-settings
Traceback (most recent call last):
  File "/usr/share/screen-resolution-extra/nvidia-polkit.py", line 75, in <module>
    operation_status = main(options)
  File "/usr/share/screen-resolution-extra/nvidia-polkit.py", line 51, in main
    exit_code = conf.backupAndWriteXorgConf([options.backup_filename, options.filename])
  File "/usr/lib/pymodules/python2.6/dbus/proxies.py", line 68, in __call__
    return self._proxy_method(*args, **keywords)
  File "/usr/lib/pymodules/python2.6/dbus/proxies.py", line 140, in __call__
    **keywords)
  File "/usr/lib/pymodules/python2.6/dbus/connection.py", line 620, in call_blocking
    message, timeout)
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.UnknownMethod: Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.6/dbus/service.py", line 649, in _message_cb
    (candidate_method, parent_method) = _method_lookup(self, method_name, interface_name)
  File "/usr/lib/pymodules/python2.6/dbus/service.py", line 244, in _method_lookup
    raise UnknownMethodException('%s is not a valid method of interface %s' % (method_name, dbus_interface))
UnknownMethodException: org.freedesktop.DBus.Error.UnknownMethod: Unknown method: backupAndWriteXorgConf is not a valid method of interface com.ubuntu.ScreenResolution.Mechanism

ERROR: Unable to open X config file '/etc/X11/xorg.conf' for writing.