How to fix gnome-settings-daemon crashing in Ubuntu 9.10 when connecting via FreeNX

The setup of the server: Ubuntu 9.10 64-bit, FreeNX server

The symptom: unable to switch between keyboard layouts, while connected via NX client - when right-clicking on keyboard indicator and choosing Keyboard Preferences, this error message raises:

Unable to start the settings manager 'gnome-settings-daemon'.
Without the GNOME settings manager running, some preferences may not take effect. This could indicate a problem with DBus, or a non-GNOME (e.g. KDE) settings manager may already be active and conflicting with the GNOME settings manager.

(No problem when logged in locally.)

When trying to start gnome-settings-daemon manually, error output is more detailed:

ostry@celsius:~$ gnome-settings-daemon
Xlib: extension "Generic Event Extension" missing on display ":1000.0".
Xlib: extension "Generic Event Extension" missing on display ":1000.0".
Xlib: extension "Generic Event Extension" missing on display ":1000.0".
Xlib: extension "Generic Event Extension" missing on display ":1000.0".
Xlib: extension "Generic Event Extension" missing on display ":1000.0".
The program 'gnome-settings-daemon' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadRequest (invalid request code or no such operation)'.
(Details: serial 105 error_code 1 request_code 150 minor_code 8)
(Note to programmers: normally, X errors are reported asynchronously;
that is, you will receive the error a while after causing it.
To debug your program, run it with the --sync command line
option to change this behavior. You can then get a meaningful
backtrace from your debugger if you break on the gdk_x_error() function.)

The solution:

start gconf-editor, then open / -> apps -> gnome_settings_daemon -> plugins -> xrandr in it and disable flag "active".

The conclusion:

There are many reports about this issue on the web, but I consider as important, to have this howto summarized here.

Enjoy!