Redirects even when subscription failed

function formalterations_form_mailchimp_lists_user_subscribe_form_alter(&$form, &$form_state) {
  $form['#submit'][] =  'formalterations_lists_user_subscribe_form_submit';
}
function formalterations_lists_user_subscribe_form_submit($form, &$form_state) {
    $form_state['redirect'] = 'node/109614';
}

When using form alter to redirect the subscription to a new page, the redirect happens even when the submission fails. I have added a variable: $form_status['error'] to check if the form submission failed.

function formalterations_form_mailchimp_lists_user_subscribe_form_alter(&$form, &$form_state) {
  $form['#submit'][] =  'formalterations_lists_user_subscribe_form_submit';
}
function formalterations_lists_user_subscribe_form_submit($form, &$form_state) {
  if($form_state['error'] == FALSE){
    $form_state['redirect'] = 'node/109614';
  } 
}