Problème de passage de python à fichier EXE

Bonjour,

J'ai récemment fait un programme en python, que j'ai ensuite transformé en executable windows avec "Auto py to exe". Lors de l'ouverture du fichier résultant, j'obtient ces erreures : 

"Failed to execute script due to unhandled
exception: The "backports" package is required; normally this is
bundled with this package, so if you get this warning, consult the
packager of your distribution."

"Traceback (most recent call last):
  File "PyInstaller\hooks\rthooks\pyi_rth_pkgres.py", line 158, in <module>
  File "PyInstaller\hooks\rthooks\pyi_rth_pkgres.py", line 36, in _pyi_rthook
  File "PyInstaller\loader\pyimod02_importers.py", line 419, in exec_module
  File "pkg_resources\__init__.py", line 68, in <module>
  File "PyInstaller\loader\pyimod02_importers.py", line 419, in exec_module
  File "pkg_resources\_vendor\jaraco\text\__init__.py", line 12, in <module>
  File "PyInstaller\loader\pyimod02_importers.py", line 419, in exec_module
  File "pkg_resources\_vendor\jaraco\context.py", line 17, in <module>
  File "pkg_resources\extern\__init__.py", line 52, in create_module
  File "pkg_resources\extern\__init__.py", line 44, in load_module
ImportError: The 'backports' package is required; normally this is bundled with this package so if you get this warning, consult the packager of your distribution."

Que faire ?

Merci d'avance