Error after creating the results

[pcav]

When selecting a few features, the analysis is run, but before displaying the results an error is thrown:

Traceback (most recent call last):
File "/home/paolo/qgis_test/python/plugins/ParallelOffset/paralleloffset.py", line 132, in run
line = LineString(h)
File "/usr/lib/python2.7/dist-packages/shapely/geometry/linestring.py", line 46, in init
self._set_coords(coordinates)
File "/usr/lib/python2.7/dist-packages/shapely/geometry/linestring.py", line 70, in _set_coords
self._geom, self._ndim = geos_linestring_from_py(coordinates)
File "/usr/lib/python2.7/dist-packages/shapely/geometry/linestring.py", line 223, in geos_linestring_from_py
"LineStrings must have at least 2 coordinate tuples")
ValueError: LineStrings must have at least 2 coordinate tuples