Uncaught TypeError: float() argument must be a string or a number

[pigreco]

Steps to reproduce

1. Add DEM raster
2. draw the line Temporare
3. save 3D dxf, window appears, type name and send;
   error!!!

Traceback (most recent call last):
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\ui\ptdockwidget.py", line 573, in saveAs
    self.outDXF()
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\ui\ptdockwidget.py", line 590, in outDXF
    PlottingTool().outDXF(self.iface, self, self.mdl, self.cboLibrary.currentText (), self.profiletoolcore.profiles)
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\tools\plottingtool.py", line 560, in outDXF
    drawing.add(dxf.polyline(points, color=7, layer=name))
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\engine.py", line 395, in polyline
    return Polyline(points, **kwargs)
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\entities.py", line 612, in __init__
    self.add_vertices(points)
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\entities.py", line 636, in add_vertices
    self.add_vertex(point)
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\entities.py", line 628, in add_vertex
    self.vertices.append(Vertex(location=point, **kwargs))
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\entities.py", line 812, in __init__
    super(Vertex, self).__init__(**default)
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\entities.py", line 196, in __init__
    self[key] = value
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\entities.py", line 204, in __setitem__
    self.attribs[key] = self._get_dxf_atom(key, value)  # factory is called
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\entities.py", line 221, in _get_dxf_atom
    return attrib.factory(value, attrib.group_code)
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\base.py", line 329, in __init__
    super(DXFPoint3D, self).__init__(coords, index_shift)
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\base.py", line 264, in __init__
    self.point = [DXFFloat(value, (pos+1)*10+index_shift) for pos, value in enumerate(coords)]
  File "C:/Users/Salvatore/.qgis2/python/plugins\profiletool\dxfwrite\base.py", line 237, in __init__
    super(DXFFloat, self).__init__(float(value), group_code)
TypeError: float() argument must be a string or a number

profiletool 4.0.2, QGIS 2.18.14 on Windows 10