Comment 12 for bug 334052

I think the root cause is linked to this messages from syslog:

Mar 18 15:09:47 lure NetworkManager: <WARN> list_connections_cb(): Couldn't retriev
e connections: No such method 'ListConnections' in interface 'org.freedesktop.Networ
kManagerSettings' at object path '/org/freedesktop/NetworkManagerSettings' (signatur
e '').
Mar 18 15:10:01 lure /USR/SBIN/CRON[5737]: (root) CMD ([ -x /usr/sbin/update-motd ]
&& /usr/sbin/update-motd 2>/dev/null)
Mar 18 15:11:01 lure NetworkManager: <WARN> connection_get_settings_cb(): connectio
n_get_settings_cb: Invalid connection: 'NMSetting8021x' / 'phase1-peaplabel' invalid
: 1

More info about my system:
HW: Lenovo x200s, Intel 5300 WiFi
SW: network-manager 0.7.1~rc3-0ubuntu2