security key and xbox adapter

i have a netgear 108mpbs wgt624 wireless firewall router
and a microsoft wireless xbox adapter(mn-740) that are
both updated and work fine with the security keys
disabled, when 128 bit security is enabled i cannot
connect to xbox live. all the lights are green on the
adapter and the wireless status screen shows all green
circles but still no xbox live connection, a wireless
laptop functions fine with security enabled. any help
would be very appreciated.