This movie attempts weave 5 stories into one but fails miserably*. The supposed link is to 9/11 but the link is actually missing. The references to 9/11 are so subtle as to be non-existent.
I viewed this movie on DVD it features the ability to view each story as a contiguous whole. After watching each story individually to try to understand the point of the movie I realized that the movie is pointless.
*(For a good example of how to weave together stories, see "Love, Actually".)
Don't waste your time with this movie