"Valid date is required for date_1" error while using drupal_form_submit()
I was facing similar kind of problem with drupal_form_submit.

After spending too much time following solution is working for me  

    $datetime = $source_node-&gt;field_date_1['und'][0]['value'] ;
    $form_state['values']['field_date_1']['und'][0]['value'] = array(
      'date' =&gt; date('d/m/Y', strtotime($datetime)),
      'time' =&gt; date('h:ia', strtotime($datetime)),
    );


Hope it will help someone