do you want a permanent solution or a quick fix?
because the alarm when off in my bro's car and he couldn't stop it so we pulled the large plug out of the bottom of the alarm box.
long term you'll have to talk to the supplier.
may be the chip in the key is not being picked up by the coil properly. check all the wires to the ignition if you can.
is it in warranty?
does the car have "NATS" as well because the two systems could be conflicting...
replace the ECU with one that doesn't have "NATS"
that's all i can think of at the mo'
let us know how you get on...