Might be worth looking into the several Locke/Christian meetings--did Christian ever actually ever say his name was Jacob? He certainly doesn't sound like whatever said 'help me.'

There was weird 'truce' talk back at the Russian guy's house they blew up in season 3--Locke et al. were accused of violating it or something. I guess that means there's still some Dharma people left on the 3rd Millennium island.