Urgent as we are going on holiday tomorow !!!!!

my dad has got a problem with his immobiliser on his escort.
it is an aftermarket one with a slot in the dash where you place a little fob into, which then deactivates the imobiliser.
but he has just gone to start it but when he placed the fob into the slot nothing happend ( normaly a flashig LED goes out but nothing )

can anyone help in any way, like how to reset it...
will disconecting the battery reset it?
or is it to do with the little fobs..

its like this... first one on the page http://www.kleenacar.co.uk/carsecurity.htm

any help would be much appreciated

chris