Unable to connect to wifi network

[fab33]

Hi,

When I try to connect to wifi ( WPA2 PSK), It doesn't work.
I check WLAN, it ask me to choose network, I enter password and ... nothing ! I try with 2 different wifi router.
If I browse another page and come back to network setting, WLAN is uncheck ...
/var/log/messages only say : moi user.err kernel: 8188eu: module is already loaded (when checking wlan)

[fab33]

It work manualy :
changing /etc/wpa_supplicant/wpa_supplicant.conf
then :
wpa_supplicant -B -iwlan0 -c/etc/wpa_supplicant/wpa_supplicant.conf -Dwext
and at last :
udhcpc -i wlan0


But how to do it properly ?