Complex rail sweeps failing

Hello Hello, 

So I have managed to develop a series of complex NURBS curve, and I now need to turn them into surfaces. My thought was to define two end curves (first image below) and simply sweep them into each other . . . that plan has failed. Does anyone know how I can turn these curves into strips. I have generated the "warp" and "weft" curves and now need to turn the curves into surface strips. My end goal is to make a weave out out them (second image below). This has confused me and I don't know why the Sweep command is yielding no output . . . bizarre!!!!!!

Image 1

Image 2