issue Drupal 7 submit button not work with theming

Hello I have an issue when i will redesign the display of form in Drupal 7.

The submit boutton not work only with a theme and not if it's displayed simply.

I try to check some information releated about this but nothing can help me at this time.

I hope there are enough information to help me

My form php:

$form=array();

$form['myform']=array(
   '#type'=>'fieldset',
   '#title' => 'Enter the NA'
);

$def_na='';
if (isset($param['NA'])) {$def_na=$param['NA'];}

$form['NA'] = array(
    '#type' => 'textfield',
    '#title' => t('Called number (NA):'),
    '#default_value' => $def_na,
    '#maxlength' => 10,
    '#minlength' => 4,
    '#required' => TRUE,
    //'#description' => t('Set this to <em>Yes</em> if you would like this category to be selected by default.'),
);

$def_period='Daily';
if (isset($param['PERIOD'])) {$def_period=$param['PERIOD'];}

$form['period'] = array(
    '#type' => 'select',
    '#title' => t('Period'),
    '#options' => array(
                        'Daily'=>'Daily',
                        'Weekly'=>'Weekly',
                        'Monthly'=>'Monthly'
                        ),
    '#default_value' => $def_period,
    //'#description' => t('Set this to <em>Yes</em> if you would like this category to be selected by default.'),
);
$form['submit'] = array('#type' => 'submit', '#value' => t('Refresh data'));
return $form;

my tpl.php page:

<table>
    <tr>
        <td>
            <?php print drupal_render($form['NA']); ?>
        </td>
        <td>
            <?php print drupal_render($form['period']); ?>
        </td>
    </tr>
    <tr>
        <td>
        <?php print drupal_render($form['submit']); ?>
        </td>
    </tr>
</table>
<?php   print drupal_render_children($form);?>

thanks for your help