Central locking problem on Ford Focus 2001 ?

The central locking is very tempremental, the key remote does not work at all, however I think this is due to worn out button contacts. The car will normally only lock the driver door when used in driver door, but will lock all doors from passenger side. Sometimes whilst driving all doors will lock or unlock if this happens the locking works properly (only temporarily) from the drivers side. I have checked fuse 63 and that is fine. I'm guessing it may be an electrical fault. Thanks for any help =)

Daniel
November 2010