Login sound doesn't want to deactivate.

Distribution: Ubuntu 9.10

When I try to deactivate the login sound in "System notifications -> KDE system" notification for the keys login and logout, the application doesn't seem to keep my options, the sound is already active. When I re-open the system notification menu, he becomes in the origininal configuration, login and logout sounds are already activated.

ProblemType: Bug
Architecture: amd64
Date: Mon Feb 1 13:07:41 2010
DistroRelease: Ubuntu 9.10
ExecutablePath: /usr/bin/systemsettings
InstallationMedia: Kubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
NonfreeKernelModules: nvidia
Package: systemsettings 4:4.3.2-0ubuntu7.1
ProcEnviron:
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
 LANGUAGE=
ProcVersionSignature: Ubuntu 2.6.31-17.54-generic
SourcePackage: kdebase-workspace
Uname: Linux 2.6.31-17-generic x86_64
XsessionErrors:
 (polkit-gnome-authentication-agent-1:2017): GLib-CRITICAL **: g_once_init_leave: assertion `initialization_value != 0' failed
 (firefox:2151): GLib-WARNING **: g_set_prgname() called multiple times
 (firefox:2228): GLib-WARNING **: g_set_prgname() called multiple times
 (firefox:2476): GLib-WARNING **: g_set_prgname() called multiple times