How to Convert GPencil strokes to Bsurface Mesh without errors?

Question

The idea was to use this script below from Convert Curves to Grease Pencil? to generate gpencil strokes from curves (poly spline type) and use them with a Bsurfaces addon (ver 1.5) to make a mesh in Blender 2.74.

import bpy
from mathutils import Vector
def convert_curve_to_gp(obj):
    #---- CHANGED ----
    scene = bpy.context.scene
    mesh = obj.data
    layer = scene.grease_pencil.layers.new("layer", set_active=True)
    frame = layer.frames.new(scene.frame_current)
    #---- /CHANGED ----
    mesh = obj.to_mesh(scene, apply_modifiers=False, settings='PREVIEW')
    for edge in mesh.edges:
        stroke = frame.strokes.new()
        stroke.draw_mode = '3DSPACE'
        stroke.points.add(2)
        stroke.points[0].co = obj.matrix_world * Vector(mesh.vertices[edge.vertices[0]].co)
        stroke.points[1].co = obj.matrix_world * Vector(mesh.vertices[edge.vertices[1]].co)
    bpy.data.meshes.remove(mesh)

obj = bpy.context.object
convert_curve_to_gp(obj)

When Bsurfaces is used by clicking on its Add surface button it generates an error:

AttributeError: 'GPENCIL_OT_SURFSK_add_surface' object has no attribute 'original_curve'

and it creates a new curve object.