Claire visits Kate with a warning in a dream

In the future, Kate wakes up in the middle of the night and looks down the hall outside her bedroom just as the phone rings. A backwards voice says "The island needs you. You have to go back before it's too late." She then hears a door open and runs to grab a gun out of the armoire. She rushes down to Aaron's room to find Claire by Aaron's bed. Kate is obviously freaked out as Claire tells her "Don't bring him back Kate. Don't you dare bring him back!." Kate then springs up in her bed with sweat dripping down her face. The phone call and Claire's appearance was a dream. Kate rushes down the hall to find Aaron asleep in his room alone. She hold's Aaron's hand while he's sleeping and tells him "I'm sorry" twice while crying.

Does Claire's appearance in the dream mean that she's dead or does she does she now have a closer communion with the island or something totally different? Does she not want Kate to take Aaron back because of the bad things that have happened or for some other reason? Questions, questions, questions.

On the door of Aaron's room, there's a painting of the white rabbit from Alice's Adventures in Wonderland. This is one of many references to the book in Lost. I also grabbed what appears to be a picture of a child on a bike, presumably Aaron, that was on top of a chest of drawers (the photo is hard to make out).