I agree with Flaneuse about Jacob needing the help and not Eko. Eko did need help, but it was too short sighted to have an extreme vision like that for one guy. Plus, in the cave where Eko was found, there were dead Dharma people. If you remember the sweat lodge vision, Ben was security and was scanning people, Jack and SawKate at that moment, but perhaps it meant he was looking for other special people like himself, to get rid of.
i don't know, I think that vision had farther ranging effects then just help out Eko. At the end of the vision, Boone made Locke get to the escalator and UP by himslef, perhaps signifying the hole he now finds himself in? Locke's faith will be tested here, and I believe he will be rewarded if he doesn't falter.