I upgraded to network-manager 0.9.0-2 and then was unable to connect to my
wireless network. Downgrading to 0.8.4-3 solved the problem.

Investigating I discovered that the SSID of my network "16" is causing the
wrong information to be passed to wpa_supplicant. When running with 0.8.4-3 the
NetworkManager log contains:

NetworkManager[8757]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare)
co
mplete.
NetworkManager[8757]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure)
starting...
NetworkManager[8757]: <info> (wlan0): device state change: 4 -> 5 (reason 0)
NetworkManager[8757]: <info> Activation (wlan0/wireless): connection 'Auto 16'
h
as security, and secrets exist.  No new secrets needed.
NetworkManager[8757]: <info> Config: added 'ssid' value '16'
NetworkManager[8757]: <info> Config: added 'scan_ssid' value '1'
NetworkManager[8757]: <info> Config: added 'key_mgmt' value 'WPA-PSK'
NetworkManager[8757]: <info> Config: added 'psk' value '<omitted>'

(note the config added 'ssid' value '16' line).

When running with 0.9.0-2 I get the following log:

NetworkManager[10076]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare)
c
omplete.
NetworkManager[10076]: <info> Activation (wlan0) Stage 2 of 5 (Device
Configure)
 starting...
NetworkManager[10076]: <info> (wlan0): device state change: prepare -> config
(r
eason 'none') [40 50 0]
NetworkManager[10076]: <info> Activation (wlan0/wireless): connection '16' has
s
ecurity, and secrets exist.  No new secrets needed.
NetworkManager[10076]: <info> Config: added 'ssid' value '^P'
NetworkManager[10076]: <info> Config: added 'scan_ssid' value '1'
NetworkManager[10076]: <info> Config: added 'key_mgmt' value 'WPA-PSK'
NetworkManager[10076]: <info> Config: added 'auth_alg' value 'OPEN'
NetworkManager[10076]: <info> Config: added 'psk' value '<omitted>'

Note that the ssid value is now ^P which is character code 16 - the actual log
contains the control character.

So it looks like something is treating the SSID as a number and converting that
to a character code instead of treating it as an opaque string.

I run gnome as my desktop with nm-applet (network-manager-gnome).

*** This bug has been marked as a duplicate of bug 660232 ***