Try wpa_supplicant -c /etc/wpa_supplicant.conf -i wlan0 -D wext -dd where wlan0 is the wireless card. There seems to be an issue with calling ndiswrapper, as I used, but I got it to work with wext. It might help. Also, make sure that your wpa_supplicant.conf file is configured correctly. I am using WPA AES. For that to work I had to set up pairwise and group as CCMP only. Plus, make sure that the password is entered in hex format and without quotes. Here's what I have:

ctrl_interface=/var/run/wpa_supplicant

#COFFEE SHOP - Using simple WEP
network={
ssid="COFFESHOP"
key_mgmt=NONE
wep_tx_keyidx=0
wep_key0=6644565378
}

#HOME - Using WPA AES
network={
ssid="HOME"
proto=WPA
key_mgmt=WPA-PSK
pairwise=CCMP
group=CCMP
#psk="willubethere4ever"
psk=365342f8362524e1834abbd953edaf8979c4de38d7601f abb30a84d769953bb3
priority=2
}

Obviously the ESSID and PSK are not what I actually use, but these are to demonstrate my setup. Let me know if it helps.