"the wireless router is not in rescue mode" ?? asus rt-n66u help

hey guys

I just got a asus rt-n66u and tried to install tomato to it for the first time, after holding down the reset button and plugin the power cable for RT-N66U and go into firmware restoration utility and upload Tomato after couple of seconds I get "the wireless router is not in rescue mode"
anybody know what I am doing wrong?
thanks