engine has intermitant cut out?

i have a kia sorento 4x4. on initial start up the car runs ok when my wife opens the front passenger door she gets in and as the door is closed the engine cuts out
to get it to re-start i have to open & close the drivers door lock & unlock the door on the key fob then it will restart this only happens on the odd occasion but it has happened twice at speed on the motorway

frank.lovell@orange.fr
January 2008