Custom User Login Template Error
By playing around with the preprocess function I seem to have fixed the errors. I changed the preprocess function to:

function cr_preprocess_user_login(&amp;$vars) {
  $vars['content_attributes_array']['class'][] = 'content';
  $vars['title_attributes_array']['class'][] = 'content';
  $vars['attributes_array']['class'][] = 'content';
  $vars['classes_array'] = array('content');
  $vars['forgot_link'] = l(t('Forgot password?'),'user/password');
}


I just added in the undefined indexes that were coming up in the errors. I'm really not completely sure what I am doing but it does seem to be removing the errors so far.

It would be great if someone could comment how this is working.