I think that this was possibly a sign that claire isn't dead because apart from locke, all who have appeared are dead, so that could be the Smoke monster or Jacob or whatever. But seen as Claire is telling Kate not to bring Aaron back, I'm thinking she's doing something to contact Kate, (let's not forget she's had visions before so it is kinda possible... Perhaps she's doing something similair to walts projection thing, as it has been suggested she's 'special.')
Hope that makes some sense
I know my grammar is really crap tonight, but i'm tired so....
