Unable to connect to WEP wifi with network-manager-gnome on xubuntu / NetworkManager No agents were available for this request.

Using Xubuntu with all latest updates.

I try to connect to network using the taskbar applet, NetworkManager eventually timesout and there is no connection. After the delay syslog shows:

NetworkManager[848]: <warn> No agents were available for this request.

Full syslog:

Aug 29 21:37:03 andrea NetworkManager[848]: <info> Activation (wlan0) starting connection 'MyWifi'
Aug 29 21:37:03 andrea NetworkManager[848]: <info> (wlan0): device state change: disconnected -> prepare (reason 'none') [30 40 0]
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare) scheduled...
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare) started...
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure) scheduled...
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Activation (wlan0) Stage 1 of 5 (Device Prepare) complete.
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure) starting...
Aug 29 21:37:03 andrea NetworkManager[848]: <info> (wlan0): device state change: prepare -> config (reason 'none') [40 50 0]
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Activation (wlan0/wireless): access point 'MyWifi' has security, but secrets are required.
Aug 29 21:37:03 andrea NetworkManager[848]: <info> (wlan0): device state change: config -> need-auth (reason 'none') [50 60 0]
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Aug 29 21:37:03 andrea NetworkManager[848]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure) complete.

delay then

Aug 29 21:37:28 andrea NetworkManager[848]: <warn> No agents were available for this request.
Aug 29 21:37:28 andrea NetworkManager[848]: <info> (wlan0): device state change: need-auth -> failed (reason 'no-secrets') [60 120 7]
Aug 29 21:37:28 andrea NetworkManager[848]: <warn> Activation (wlan0) failed for access point (MyWifi)
Aug 29 21:37:28 andrea NetworkManager[848]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Aug 29 21:37:28 andrea NetworkManager[848]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Aug 29 21:37:28 andrea NetworkManager[848]: <info> Marking connection 'MyWifi' invalid.
Aug 29 21:37:28 andrea NetworkManager[848]: <warn> Activation (wlan0) failed.
Aug 29 21:37:28 andrea NetworkManager[848]: <info> (wlan0): device state change: failed -> disconnected (reason 'none') [120 30 0]
Aug 29 21:37:28 andrea NetworkManager[848]: <info> (wlan0): deactivating device (reason 'none') [0]
Aug 29 21:37:28 andrea NetworkManager[848]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: network-manager-gnome 0.9.4.1-0ubuntu2
ProcVersionSignature: Ubuntu 3.2.0-29.46-generic 3.2.24
Uname: Linux 3.2.0-29-generic i686
ApportVersion: 2.0.1-0ubuntu12
Architecture: i386
Date: Wed Aug 29 22:02:34 2012
EcryptfsInUse: Yes
InstallationMedia: Xubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
IpRoute:
 default via 192.168.1.1 dev wlan0 proto static
 169.254.0.0/16 dev wlan0 scope link metric 1000
 192.168.1.0/24 dev wlan0 proto kernel scope link src 192.168.1.105 metric 2
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: network-manager-applet
UpgradeStatus: Upgraded to precise on 2012-02-14 (197 days ago)
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH
 wlan0 802-11-wireless connected /org/freedesktop/NetworkManager/Devices/1
 eth0 802-3-ethernet unmanaged /org/freedesktop/NetworkManager/Devices/0
nmcli-nm:
 RUNNING VERSION STATE NET-ENABLED WIFI-HARDWARE WIFI WWAN-HARDWARE WWAN
 running 0.9.4.0 connected enabled enabled enabled enabled disabled