Error when following along with the tutorial on the Django website

I am following the django tutorial here. I have copied everything exactly. After the part where you enter the python manage.py sql polls command, it returns:

Error:A开发者_开发知识库pp with the label polls could not be found. Are you sure yuor 
INSTALLED_APPS setting is correct?

I have the site installed in /home/kevin/crossen/crossen, and the dir listing is

__init__.py
__init__.pyc
manage.py
polls(dir)
settings.py
settings.pyc
testdb(sqlite3 database)
test.db(0bytes)
urls.py
urls.pyc

and the end of my settings.py file looks like this:

INSTALLED_APPS=(
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.sites',
'crossen.polls'
)

The crossen.polls following the mystie.polls convention found in the guide. I have tried it with just polls, same error. Not sure whats wrong, thanks in advance.

EDIT

Polls dir is:

__init__.py
__init__.pyc
models.py
models.pyc
tests.py
views.py

• Is there an __init__.py file in the polls directory?
• Is /home/kevin/crossen on your python path?

To check the path, do:

$ python -c "import sys; print sys.path"

open 'site/settings.py' file and change the INSTALLED_APPS setting to include the string 'your_app'