Ford Fiesta zetec won't lock?

I have a Ford Fiesta zetec 06 and there's a problem with the locking system every time I try locking it from the buttons on the key it locks then unlocks straight away also does the same thing when I put the key in manually any help?

My Focus started that double bounce, but the key worked in the passenger door.
I did the remote reset, with the ignition off, hold the lock and unlock buttons on the remote for over 4 secs, the indicators should flash and then work as normal.

With all the doors closed, look in & see IF the dome light is still on… IF the dome light stays on, maybe the car thinks one of the doors isn't closed… There are electric switches in each door somewhere that tell the computer if that door is open or closed…