Failed to use Theano as backend for vgg16.py

[shrimanti]

Hi,
I am trying to run the code vgg16.py using Theano backend as the network weights are in Theano.
I have set
from keras import backend as K
K.set_image_dim_ordering('th')
But still it is using Thensorflow and giving me the error.

self._session = tf_session.TF_NewSession(self._graph._c_graph, opts)
tensorflow.python.framework.errors_impl.InternalError: Failed to create session.

Process finished with exit code 1