Surface could not be fitted

Hi, I am trying to do a surface with ripples and I was following Michael Pryor's tutorial step by step (http://formularch.blogspot.mx/), however the last component, the one that is supposed to create the surface itself gives me following error: "Surface could not be fitted". I have tried moving everything I could and I can't find a solution. I am attaching the Rhino file with the base Surface and the attraction curve, and also the Grasshopper definition, could someone please take a look at it?

Thanks in advance.