http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=37332504
Take a look at the illustrating pictures, that horizontal red line is really obvious! The higher the resolution and the quality of the image, the more obvious the red line! >:-[
And read also this yet another previous report of the same issue:-
http://forums.dpreview.com/forums/read.asp?forum=1036&message=37090794