hmmm....
unfortunately I don't have much experience texturing nurbs, cause I work mostly in polys. But there's almost no way you should be getting that, in any case..... The resuly you have there seems more to be what you'd get if you automapped a poly cube; there doesn't appear to any extra faces....

Are you sure you're working in Nurbs? How did you make that, cause nurbs tend to try to smooth their edges..... Otherwise, I have no idea what's going on there....