A single tiledbackground is not the best of ways to go I think.
In my example it works because the texture is power of 2 (128) and the WindowWidth is too.
If your texture file (the one you "feed" the TiledBackground) is power of two and the WindowHeight is too, it should work "seamlessly".
Make sure the height of your tiledbackground matches the WindowHeight and you should have it.