OFFSET ERROR : data conversion fail from brep to surface

I'm following a youtube tutorial for grashopper on making a parametric shape, and for some reason I keep getting the error when it comes to the offset part (9:11)I'll link the video below. I re-tried the same tutorial multiple times, following it to the T but when it comes to that part it doesn't seem to work for me. 

I know the differences between my work and the video begin when I attach the weave to the loft and when I attach the panel it tells me untrimmed surface followed by numerous open brep while in the video it only says untrimmed surface throughout. 

I can't seem to figure out what I'm doing wrong. 

I'm also linking my .gh file

Any help will be greatly appreciated 

Youtube Tutorial:

https://www.youtube.com/watch?v=XJQgG5MRnNw&t=492s