network-manager displays error message when trying to edit wireless connections

[Daniel Told]

When trying to edit the properties of *some* of my saved wireless networks (not all of them, strangely), the network manager gives an error message saying "Error initializing editor, No agents were available for this request."

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: network-manager 0.9.2.0+git201202161854.8572ecf-0ubuntu7
ProcVersionSignature: Ubuntu 3.2.0-18.29-generic 3.2.9
Uname: Linux 3.2.0-18-generic i686
NonfreeKernelModules: openafs
ApportVersion: 1.94.1-0ubuntu2
Architecture: i386
Date: Tue Mar 13 06:04:03 2012
EcryptfsInUse: Yes
IfupdownConfig:
 auto lo
 iface lo inet loopback
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110413)
IpRoute:
 default via 192.168.178.1 dev wlan0 proto static
 169.254.0.0/16 dev wlan0 scope link metric 1000
 192.168.178.0/24 dev wlan0 proto kernel scope link src 192.168.178.20 metric 2
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
SourcePackage: network-manager
UpgradeStatus: Upgraded to precise on 2012-03-12 (0 days ago)
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH
 wlan0 802-11-wireless connected /org/freedesktop/NetworkManager/Devices/1
 eth0 802-3-ethernet unavailable /org/freedesktop/NetworkManager/Devices/0
nmcli-nm:
 RUNNING VERSION STATE NET-ENABLED WIFI-HARDWARE WIFI WWAN-HARDWARE WWAN
 running 0.9.3.0 connected enabled enabled enabled enabled disabled