With Fedora 11 (0.12.20090519svn.fc11), I still experience this problem.
Here is the log, with plasmoid:

Nov  6 11:06:16 bastard kernel: ADDRCONF(NETDEV_UP): wlan0: link is not ready
Nov  6 11:06:16 bastard NetworkManager: <info>  (wlan0): device state change: 2 -> 3 (reason 0)
Nov  6 11:06:16 bastard NetworkManager: <info>  (wlan0): supplicant interface state:  starting -> ready
Nov  6 11:06:46 bastard NetworkManager: <WARN>  wait_for_connection_expired(): Connection (2) /org/freedesktop/NetworkManagerSettings/1 failed to activate (timeout): (0) Connection was not provided by any settings service

altough with nm-applet, I can connect to the network without any problem.

Here is the log, of nm-applet connecting to the same network:

Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) starting connection 'Auto GUESTS'
Nov  6 11:07:15 bastard NetworkManager: <info>  (wlan0): device state change: 3 -> 4 (reason 0)
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) scheduled...
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) started...
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) scheduled...
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) complete.
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) starting...
Nov  6 11:07:15 bastard NetworkManager: <info>  (wlan0): device state change: 4 -> 5 (reason 0)
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0/wireless): access point 'Auto GUESTS' has security, but secrets are required.
Nov  6 11:07:15 bastard NetworkManager: <info>  (wlan0): device state change: 5 -> 6 (reason 0)
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) complete.
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) scheduled...
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) started...
Nov  6 11:07:15 bastard NetworkManager: <info>  (wlan0): device state change: 6 -> 4 (reason 0)
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) scheduled...
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) complete.
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) starting...
Nov  6 11:07:15 bastard NetworkManager: <info>  (wlan0): device state change: 4 -> 5 (reason 0)
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0/wireless): connection 'Auto GUESTS' has security, and secrets exist.  No new secrets needed.
Nov  6 11:07:15 bastard NetworkManager: <info>  Config: added 'ssid' value 'GUESTS'
Nov  6 11:07:15 bastard NetworkManager: <info>  Config: added 'scan_ssid' value '1'
Nov  6 11:07:15 bastard NetworkManager: <info>  Config: added 'key_mgmt' value 'WPA-PSK'
Nov  6 11:07:15 bastard NetworkManager: <info>  Config: added 'psk' value '<omitted>'
Nov  6 11:07:15 bastard NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) complete.
Nov  6 11:07:15 bastard NetworkManager: <info>  Config: set interface ap_scan to 1
Nov  6 11:07:15 bastard NetworkManager: <info>  (wlan0): supplicant connection state:  inactive -> scanning
Nov  6 11:07:18 bastard NetworkManager: <info>  (wlan0): supplicant connection state:  scanning -> associating
Nov  6 11:07:18 bastard kernel: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
Nov  6 11:07:18 bastard NetworkManager: <info>  (wlan0): supplicant connection state:  associating -> associated

If any developer needs some more please just ask.

Best regards!