Gridshell Components Error

Hi,

I am trying to use the gridshell components tools (http://www.grasshopper3d.com/profiles/blogs/latest-version-of-grids...) to create a pattern of sweeps upon a surface. However the centrelines component is returning an error message. Any advice on what the problem might be would be great. 

Additionally, the essential aim of the exercise is to sweep all the radial and lateral curves with a rectangular mesh which aligns itself to the surface normals at all points. The aim is to create a set of structure lines which can be skinned on either side with a surface. If there is another way to achieve this I would be most grateful. 

Definition and screenshot attached. 

Tom