I can't recall which season it is, or what it is he's burying (Nikki/Paulo story never caught my attention, go figure haha), BUT in one episode Paulo is burying something and Locke comes up to him and says something along the lines of "things don't stay buring too long on this island" or something along those lines.
That scene always stuck with me. At first i thought it meant Nikki and Paulo were going to somehow survive, since they of course were buried. But now that we're heading into the last season, I don't really see any reason to bring them back.
Which makes me wonder if maybe Locke was alluding to something else. Could it be, that Locke WAS dead at that point? And MIB was using his body and it was actually him that said the line to Paulo? Maybe hinting at the fact that he's still around, etc etc.
I, for one, don't think so, but I thought I'd just throw that idea out there and get some other theories. At this point, now, I just feel like it was a little easter egg the writers put in the script foreshadowing the burial of Nikki and Paulo, but something in me wants to believe it has more to do with the story.