Something just didn't sound right to me reading the posts in this thread. I haven't flown the A330 for a few months but row 24 didn't sound correct as being the exit row. Sure enough, I looked in my manual AND on the US website and the exit row is Row 23!! No wonder the window seats were available! If I were you I would double check with US or whoever was changing your seats, but I would go for 23 C D E or F.
Sorry for the confusion, I should have satisfied my curiousity before posting my first reply.