MultipleObjectsReturned traceback

Environment:


Request Method: POST
Request URL: http://corecrm.local/admin/venue/booth/add/

Django Version: 1.5.5
Python Version: 2.7.3
Installed Applications:
('django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.gis',
 'nested_inlines',
 'django.contrib.admin',
 'south',
 'rest_framework',
 'djcelery',
 'django_extensions',
 'django.contrib.humanize',
 'corecrm',
 'people',
 'groupop',
 'venue',
 'tag',
 'booking',
 'enquiry',
 'promotion',
 'cinema',
 'reports',
 'debug_toolbar')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'audit_log.middleware.UserLoggingMiddleware',
 'debug_toolbar.middleware.DebugToolbarMiddleware')


Traceback:
File "C:\Python27\lib\site-packages\django\core\handlers\base.py" in get_response
  115.                         response = callback(request, *callback_args, **callback_kwargs)
File "C:\Python27\lib\site-packages\django\contrib\admin\options.py" in wrapper
  372.                 return self.admin_site.admin_view(view)(*args, **kwargs)
File "C:\Python27\lib\site-packages\django\utils\decorators.py" in _wrapped_view
  91.                     response = view_func(request, *args, **kwargs)
File "C:\Python27\lib\site-packages\django\views\decorators\cache.py" in _wrapped_view_func
  89.         response = view_func(request, *args, **kwargs)
File "C:\Python27\lib\site-packages\django\contrib\admin\sites.py" in inner
  202.             return view(request, *args, **kwargs)
File "C:\Python27\lib\site-packages\django\utils\decorators.py" in _wrapper
  25.             return bound_func(*args, **kwargs)
File "C:\Python27\lib\site-packages\django\utils\decorators.py" in _wrapped_view
  91.                     response = view_func(request, *args, **kwargs)
File "C:\Python27\lib\site-packages\django\utils\decorators.py" in bound_func
  21.                 return func(self, *args2, **kwargs2)
File "C:\Python27\lib\site-packages\django\db\transaction.py" in inner
  223.                 return func(*args, **kwargs)
File "C:\Python27\lib\site-packages\django\contrib\admin\options.py" in add_view
  989.             if form.is_valid():
File "C:\Python27\lib\site-packages\django\forms\forms.py" in is_valid
  126.         return self.is_bound and not bool(self.errors)
File "C:\Python27\lib\site-packages\django\forms\forms.py" in _get_errors
  117.             self.full_clean()
File "C:\Python27\lib\site-packages\django\forms\forms.py" in full_clean
  272.         self._clean_fields()
File "C:\Python27\lib\site-packages\django\forms\forms.py" in _clean_fields
  287.                     value = field.clean(value)
File "C:\Python27\lib\site-packages\django\forms\fields.py" in clean
  154.         value = self.to_python(value)
File "C:\Python27\lib\site-packages\django\forms\models.py" in to_python
  1009.             value = self.queryset.get(**{key: value})
File "C:\Python27\lib\site-packages\django\db\models\query.py" in get
  408.             (self.model._meta.object_name, num))

Exception Type: MultipleObjectsReturned at /admin/venue/booth/add/
Exception Value: get() returned more than one AreaLayout -- it returned 2!