Error when developing forms Fatal error: Cannot use string offset as an array form.inc on line 985

In my case the error Fatal error: Cannot use string offset as an array form.inc on line 985, was caused by a missing declaration of the form array.

<?php
   $form = array(); //If this is not present it will cause the fatal error

   $form['logs']['copy'] = array(
      '#type' => 'checkbox',
       '#return_value' => 1,
       '#default_value' => 0,
      '#title' => t('Delete all logs for this account.'),
    );

    $form['logs']['account'] = array(
      '#type' => 'hidden',
      '#value' => $account_name,
    );

     $form['logs']['submit'] = array(
    '#type' => 'submit',
    '#title' => 'Delete',
    '#submit' => array('support_filter_delete_logs_form_submit'),
    '#value' => t("Delete"),
    '#weight' => 3,
  );

  return $form;
?>
Knowledge keywords: 
Drupal 6.x
forms