Central locking?

Hi. I need a little help!!
I have a Renault Megane Estate Sports Tourer. 2003 plate. I am having trouble, today after setting off the car was warning of an open door on the display panel and after stopping and checking there were no doors open. Each time I stop the car it tries to lock the doors and gives a single Beep. Can anybody please help, I cannot lock the doors so will have to disconnect the battery tonight as there are no Garages open today being Sunday.
Could this possibly be a fuse and iff so where do I check it out?