Issue with Django admin registering an inline user

I'm currently working on a django project. I'm attempting to add a UserProfile model inline to my User model. In my models.py I have:

class UserProfile(models.Model):
    '''
    Extension to the User model in django admin.
    '''
    user = models.ForeignKey(User)
    site_role = models.CharField(max_length=128, choices=SITE_ROLE)
    signature = models.CharField(max_length=128)
    position_title = models.CharField(max_length=128)
    on_duty = models.BooleanField(default=False)
    on_duty_order = models.IntegerField()

In my admin.py I have:

class UserProfileInline(admin.StackedInline):
    model = UserProfile

class UserAdmin(admin.ModelAdmin):
    inlines = [UserProfileInline]


admin.site.unregister(User)
admin.site.register(User, UserAdmin)

When I run the development server (yes, I have restarted it) I get the following exception:

NotRegistered at /admin
The model User is not registered

This exception is coming from the admin.site.unregister(User) line.

However, when I comment out that line, I get the following exception:

AlreadyRegistered at /admin
The model User is already registered

Something about my django setup seems to be a little bi-polar. I've spent an hour or so researching this problem and the code I have seems to work great for others. Does anyone have any insight into why this might be happening?

Thanks, Travis

my guess is that you either are doing some crazy module importing... or... you have an ordering problem in your settings.INSTALLED_APPS list. Make sure that 'django.contrib.auth' appears on your list before your app that is replacing the default admin. The list should look something like this:

INSTALLED_APPS = (
    # django apps first
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.sites',
    'django.contrib.messages',
    'django.contrib.admin',

    # your stuff from here on
    'yourproject.userstuff',
)

That way django's app registers the User model, and then you unregister and re-register it with your own ModelAdmin.