problem installing FTDI drivers on Angstrom BB

i have problem installing FTDI drivers(i need it for communication bet
Arduino and BB)

after mount -a command following error is displayed

<3>drivers/usb/core/inode.c: usbfs: unrecognised mount option
"mode=0666" or missing value

drivers/usb/core/inode.c: usbfs: unrecognised mount option "mode=0666"
or missing value

<4>drivers/usb/core/inode.c: usbfs: mount parameter error:
drivers/usb/core/inode.c: usbfs: mount parameter error:
mount: none already mounted or /proc/bus/usb busy
mount: according to mtab, usbfs is already mounted on /proc/bus/usb

please help me out