Fab4,
have you still got that problem with the seamless textures still?

Is your texture a "power of 8" in width and height? (Because the image youve posted isnt)

AFAIK, all textures need to be a power-of-eight in dimension for
direct-x to handle them properly.
eg sizes: 8x8, 16x64, 256x1024, 512x512. Them sort of numbers...