So a quick follow up. I've still not found a solution, but after changing the logs and clearing the cache in PHP, I could see the error that the module "bunch" could not be found, so I commented that line out and now get:
{'script_result': {'error': "'dict' object has no attribute 'session'"}, 'resource': '', 'request': {'parameters': {'login': 'True'}, 'payload': {'first_name': 'ggg', 'last_name': 'ddd', 'display_name': 'ddd', 'email': 'ya$
so, a little close, but still not quite there.