python different import behaviour on osx and ubuntu

I have the same python project on 2 computers running osx and ubuntu 14.04

I am running a script in the phd_thesis.non_linear_features_selection folder At the beginning of the script I import some functions as:

import numpy as np
#from phd_thesis.non_linear_features_selection.example_datasets.polynomial_datasets import *   # it works only on OSX                                                                                             
from example_datasets.polynomial_datasets import * # it works only on ubuntu

I have to use a different import path on osx and ubuntu. Why is this happening? How can I have a single import that works on both os?

EDIT: The project is a bit messy. Here the tree structure:

onbeo@donbeo-OptiPlex-790:~/Dropbox/pythoncode/phd_thesis/non_linear_features_selection$ tree
.
|-- checkpoint
|-- deep_learning
|   |-- autoencoder_fsca.py
|   |-- autoencoder_fsca.py~
|   |-- autoencoder_j2m.py
|   |-- autoencoder_j2m.py~
|   |-- autoencoder_magic.ckpt
|   |-- autoencoder_NC60.ckpt
|   |-- autoencoder_parkinson.ckpt
|   |-- checkpoint
|   |-- mnist_autoencoder.ckpt
|   |-- nn_j2m.py
|   |-- nn_j2m.py~
|   |-- nn_selector_magic_nino.py
|   |-- nn_selector_magic_nino.py~
|   `-- results
|-- elm_fsca_j2m.py
|-- elm_fsca_j2m.py~
|-- elm_fsca_poly_example.py
|-- elm_fsca_poly_example.py~
|-- elm_fsca_various_datasets.py
|-- elm_fsca_various_datasets.py~
|-- example_datasets
|   |-- __init__.py
|   |-- polynomial_datasets.py
|   |-- polynomial_datasets.py~
|   `-- __pycache__
|       |-- __init__.cpython-34.pyc
|       `-- polynomial_datasets.cpython-34.pyc
|-- examples_issc2016.py
|-- examples_issc2016.py~
|-- __init__.py
|-- j2m_results_plot.py
|-- j2m_results_plot.py~
|-- neural_network_lasso.py
|-- neural_network_lasso.py~
|-- non_linear_regression_examples_plot.py
|-- non_linear_regression_examples_plot.py~
|-- non_linear_regression_examples.py
|-- non_linear_regression_examples.py~
|-- non_linear_regression_simulated_data_tables.py
|-- non_linear_regression_simulated_data_tables.py~
|-- parity_function_example.py
|-- parity_function_example.py~
|-- polynomial_data_example.py
|-- polynomial_data_example.py~
|-- __pycache__
|   `-- __init__.cpython-34.pyc
|-- real_data_example.py
`-- results

The script that I am running is |-- polynomial_data_example.py (6th element from the bottom)

Copyright Notice：Content Author:「Donbeo」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/36432203/python-different-import-behaviour-on-osx-and-ubuntu