I\'ve got this error after I\'ve installed these two apps: https://github.com/dyve/django-bootstrap3 and https://github.com/django-admin-bootstrapped/django-admin-bootstrapp
It appears to be that in Django 1.7, applications have to be labeled uniquely. This is a new requirement and causes therefore new conflicts. In your example, there are two apps named bootstrap3: the bootstrap3 extension and the django_admin_bootstrapped.bootstrap3 extension -- Django only seems to honor the package name, rather than the full package path.
Django 1.7 has instructions on how to solve this problem here: https://docs.djangoproject.com/en/1.7/ref/applications/#for-application-authors
For now, it seems that you have to wait for the developers of those two apps to release a fix. There already exist matching issues in both projects:
Well, I just noticed that those two issues were submitted by you. :) Nevertheless, I'll leave the answer for future reference.