Nissan NATS is keeping me from starting!?

Hi all,

I Have a 2003 Nissan Amera 1.8 Tekna. In the past year I didn´t have any trouble whatsoever with it.. engine runs like a charm. A month or so ago my battery of the primary key died, so I replaced it. Since then every now and then when I try to start the car, it showes a little red key-shaped light in the dash and the digital display will say: PLEASE WAIT. When i wait for a minute it will say: SECURE. It does not start though and I have to switch on and off repeadetly for 20 minutes to get it to start! (and then it runs fine) It will only start when the little red key light is not on.. so Im thinking it is somehow the NATS system. Can Anyone tell me if there is a way to solve this? My dealer doesnt seem to have the knowhow..

Thanks very much in advance!!