My custom-built 2.6.32 kernel cannot connect to any WPA-protected network.

The kernel includes (probably?) everything that should be needed for wifi, including IPv4 network support (IPv6 is disabled), the ath5k wireless driver (which is used in the generic Ubuntu 2.6.31 kernel) and all crypto APIs.

The card is being detected, however, iwlist scan returns

wlan0     Failed to read scan data : Network is down

and network-manager log says

<info>  (wlan0): driver supports SSID scans (scan_capa 0x01).
<info>  (wlan0): new 802.11 WiFi device (driver: 'ath5k')
<info>  (wlan0): exported as /org/freedesktop/NetworkManager/Devices/1
<info>  (wlan0): now managed
<info>  (wlan0): device state change: 1 -> 2 (reason 2)
<info>  (wlan0): bringing up device.
<info>  (wlan0): preparing device.
<info>  (wlan0): deactivating device (reason: 2).
supplicant_interface_acquire: assertion `mgr_state == NM_SUPPLICANT_MANAGER_STATE_IDLE' failed
<info>  modem-manager is now available
<WARN>  default_adapter_cb(): bluez error getting default adapter: The name org.bluez was not provided by any .service files
<info>  Trying to start the supplicant...
<info>  (wlan0): supplicant manager state:  down -> idle
<info>  (wlan0): device state change: 2 -> 3 (reason 0)
<WARN>  nm_supplicant_interface_add_cb(): Unexpected supplicant error getting interface: wpa_supplicant couldn't grab this interface.

The exact same configuration works with the generic kernel.

Is anything except wifi and crypto api needed for wi-fi to work?