Remember how the one 'Castigliani brother' was staring at Diane at the party? Then he showed up in the dream puking his espresso. I have this theory that Diane is a call-girl on the mend, and this guy, apparently someone in the movie business, happened to recognize her at the party.
Also recall the close-up of Diane's coffee cup just before she sees him - there's a little foam or something on the top of her coffee, which probably led to the 'dream-espresso'. Her feeling ill at the party might be what's represented by the guy throwing up in the dream (of course this theory assumes the first part of the movie is a dream).




