Use getOrCreateTaskSubscriptionForTask in the TaskSubscription View.
#!/usr/bin/env python
if __name__ == "__main__":
import sys
name = sys.argv[0]
args = ' '.join(sys.argv[1:])
print >> sys.stderr, "%s has been moved into django-admin.py" % name
print >> sys.stderr, 'Please run "django-admin.py makemessages %s" instead.'% args
print >> sys.stderr
sys.exit(1)