[PROBLEM] Failed to bring up wlan0

[sekhar]

I have installed xbian and unable to get wireless working, can someone please help? Below are details:
Wireless adapter: EDIMAX EW-7811Un
uname - a
Linux xbian 3.6.11+ #10 PREEMPT Thu Jan 3 … armv61 GNU/Linux
…
Error for wireless request "Set Power Management" (8B2C) :
SET failed on device wlan0 ; Function not implemented.
wpa_supplicant: /sbin/ wpa_supplicant daemon failed to start
Failed to bring up wlan0
…
My /etc/network/interfaces file is listed below:
auto lo

iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
iface wlan0 inet dhcp

wpa-ssid "wireless"
wpa-psk "12345"
wireless-power off

My /etc/wpa_supplicant/wpa_supplicant.conf file is listed below:
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1