Probleme de connection WIFI

Bonjour,

J'ai un soucis de connection avec mon Raspberry PI sous Raspbmc,
ma clé USB WIFI est une TP-Link TL-WN722N,
j'ai suivi cette page: https://elinux.org/RPi_Peripherals#Wireless:_TP-Link_TL-WN722N_USB_wireless_adapter_.28Debian_6.29 pour installer le driver de cette clé et j'arrive à faire des scan,
j'ai suivi cette page: https://forums.commentcamarche.net/forum/affich-37604408-configurer-le-wifi-sous-linux-debian pour configurer mon fichier /etc/network/interfaces:

auto lo

iface lo inet loopback
iface eth0 inet dhcp

# The wireless interface
auto wlan0
iface wlan0 inet dhcp
   wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

et mon fichier /etc/wpa_supplicant/wpa_supplicant.conf:

ctrl_interface=/var/run/wpa_supplicant
eapol_version=1
ap_scan=1
fast_reauth=1

network={
    ssid="MimiNetwork"
    scan_ssid=1    
    proto=WPA
    key_mgmt=WPA-PSK
    psk=monpassword
    priority=5
}

quand je lance la commande

sudo ifup wlan0

j'obtiens:

wpa_supplicant: /sbin/wpa_supplicant daemon failed to start
run-parts: /etc/network/if-pre-up.d/wpasupplicant exited with return code 1
Internet Systems Consortium DHCP Client 4.2.2
Copyright 2004-2011 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/wlan0/10:fe:ed:28:0a:dc
Sending on   LPF/wlan0/10:fe:ed:28:0a:dc
Sending on   Socket/fallback
DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 8
DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 17
DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 20
DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 9
DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 7
No DHCPOFFERS received.
No working leases in persistent database - sleeping.
/etc/network/if-up.d/secure-rmc: line 9: let: remainder =  % 2: syntax error: operand expected (error token is "% 2")
/etc/network/if-up.d/secure-rmc: line 10: let: result = ( / 2): syntax error: operand expected (error token is "/ 2)")

les 2 dernières lignes se répètent sans arrêt.

Mon point d'accès est un Netgear WG602v4,
Security type: WPA-PSK,
Encryption Type: TKIP

Quelqu'un aurait une piste?

Merci d'avance!