Header image repeat has broken

Hello,

I’ve installed the background manager and got it working, however it seems to break my header image, as you can see a line appears at the end of each image. http://wuvoo.co.uk/sci-fi-cakes/ and a page with the header looking correct is http://wuvoo.co.uk/

Any help would be much appreciated.

http://wordpress.org/plugins/background-manager/