We could not complete your
iTunes request (error 4002) Any ideas?
Probably just a server issue, or a connection timeout, or some other minor issue. Try again, and I bet it will work. It happens to me sometimes when I try to navigate the iTunes Store.
Try signing out of iTunes Store, then sign back in.
If you have match, hold shift key whilst signing out of match, then sign back into match.
Retrieving data ...