Remember how Charlie said that "just because no one has seen the monster in two weeks doesn't mean it won't get hungry again"? That gives us a pretty good idea of the timeline on the island. Correct me if I am wrong, but the last person who saw the monster was Locke, right? So it has been roughly two weeks from then.

How many episodes has that been?

I thought that Locke didn't tell anyone what he saw....Didn't he say that he didn't see it? Cuz if that's the case, then Charlie wouldn't know about it and would be referring to the previous sighting.

Well, don't forget Michael and Kate saw it heading in Locke's direction, so... also, given that Shannon said Locke and Boone had been going into the forest for 4 days now, that would mean that the previous 10 episodes had occurred in 8 days. Since, in episode 4, Jack says something about it being 4 days already, that would mean 6 episodes in 4 days. I think it's two weeks since Kate/Michael's sighting.

Remember how Charlie said that "just because no one has seen the monster in two weeks doesn't mean it won't get hungry again"?

Actually, having Charlie say that makes no sense, since as far as he knows, NO ONE has been eaten by the 'monster'. The pilot was still physically there, I'm sure Charlie could see that much. So maybe 'the monster hasn't KILLED anyone in two weeks' should be the line? Plus, there are wild boars on the island so why would he think the monster eats only people? And yes the distinction between 'killed' and 'eaten' is VERY important. You can be killed by a rhino but you won't be eaten by him...I don't think. But you get my point.

Maybe he was just trying to act innocent, like he doesn't know what's really going? Such as his line to Rose about no one looking for them. He KNOWS it's the truth but doesn't tell this to Rose.