Basic questions about packages/modules.

[Negroup]

Hi, first of all sorry for boring you with a such simple request. I'm
using Python since few days, and I like it even if I'm not yet in
confidence. I'd like to organize my programs in hierarchical
structures, thus I thought that packages could be the solution,
however I have some difficulties understanding their utilization (even
after reading chapter 6 of the tutorial, about modules).

Now an example (silly) to clarify my doubts:

This is the structure:
main.py
importers/
    __init__.py (empty)
    importer1.py
config/
    __init__.py (empty)
    parameters.py

main.py
=======
from importers import importer1
print importer1.display()

importers/importer1.py
======================
from config import parameters
def display():
    return '-' * parameters.counter

config/parameters.py
====================
counter = 5


All works fine when I run "python main.py", while I get an error
trying to run "python importers/importer1.py":

Traceback (most recent call last):
  File "importers/importer1.py", line 1, in ?
    from config import parameters
ImportError: No module named config

Can you explain why does that happen? It prevents me to test
importer1.py alone.

TIA,
negroup