freelander 1,8 sops after 3 seconds

At first I have to apologize for my simple incorrect English language, I'm a Norwegian.

My Freelander 1,8 1999 stops 3 sec after it's started.
If I try to start again, I need to lock and unlock the sentral lock first, then it will only run for 3 sec.
The petrol pump is running, and it still have power after the engine stops.

Is this a immobilizer-problem?

I only have a blank metal key (and remote fob).
Do this model need a special key for immobilizer?

You should be fine with the fob and key as the immobiliser is controlled from the fob, it does sound like you may have an immobiliser problem but I am no expert.

Immobilizer runs off the fob.

It does sound like an immobilizer problem, as this is precisely what your immobilizer will do when its not matched up properly.

I suggest disconnecting the battery for 30 minutes then trying again. Is the red LED blinking on the dash when you start the car?

Thank's

I've got some help from the local workshop, with programming a new key.
No it runs perfect.
I have just bought a new key, and I wonder if there is some trick to install the new key without programming?
I know from other brands that the new key can be used after switching the old key on and off several times somehow.
Im I into somthing, or is this unknown in the Freelander world?