django - What is this AttributeError in django mongodb, and how do I prevent this?

Question

I keep running into this error for both .raw_query and .filter,

it happens when I do a simple query like this :

Tried google but did not have much luck except this .

Is that the same issue? And how do I update the schema to prevent this from happening?

from app.models import Poll
import Datetime

polls = Poll.objects.filter(created_at__gte=datetime.datetime(2013,5,1))
for p  in polls: 
    print p

Error:

AttributeError: 'unicode' object has no attribute 'iteritems'