Shouldn't have anything to do with the contents of the playbook.
If you're using -c paramiko, can you try with -c ssh to see if that
makes a difference? Check ports, see if you can SSH in normally,
see if you really want to connect as root, etc?
I had the same problem.
You have to install sshpass first.
And then you should run the playbook with --ask-pass option like:
ansible-playbook --ask-pass playbook.yml -c ssh
Can you please file a ticket at github.com/ansible/ansible ?
We should yell about not finding sshpass in this case.