I imported an stl file in vcarve and then created the toolpath, I do not think there is a way to see the vectors. Also, this method has worked very successfully in the past. The only nodes I can edit are the outline of the stl.
I tried importing the arching of the model as a subd as well as a nurbs, made no difference. Also from my experience vcarve can handle meshes with 1 million polygons without any problem, but I think my file is much smaller than that. The errors also happen in the profile toolpath. The profile toolpath has about 100 nodes.
What I could do is recreate the toolpath again in vcarve in a lower modelling resolution, but somehow I would not expect a change.