Checkbox Privacy: errore di validazione in ogni caso

[Adenina]

Ho integrato nel template dei contatti di un tema wordpress il checkbox della privacy ( di default non presente).
Il problema è che ottengo l'errore di validazione (*Il consenso è obbligatorio*) che io spunti o no il checkbox della Privacy.
Premetto che sono inesperta di PHP.

Posto il codice della pagina ( le parti che ho inserito sono commentate)

Grazie in anticipo!

  <?php
    /*Template Name: Contact form*/
?>
<?php global $SMTheme;?>
<?php  

    if (isset($_POST[$_SESSION['commentinput']])&&$form=$_POST[$_SESSION['commentinput']]) {
        $msg='';
        $error='';
        $errorcode='red';
        $privacy=$_POST['privacy']; // parte che ho inserito
        foreach ($SMTheme->get( 'contactform', 'contactform' ) as $key=>$detail) {
            if ($detail['req']=='required'&&$form[$key]=='') $error.='Field '.$detail['ttl']." is required<br />";
            if ($detail['regex']!=''&&!eregi(stripslashes($detail['regex']),$form[$key])) {
                $error.='Field '.$detail['ttl']." is not valid<br />";
            }
            $msg.=$detail['ttl'].": ".$form[$key]."\r\n";
        }
        
//parte che ho inserito
            if ($privacy !=1) {
        $error.='Il consenso è obbligatorio<br />';
        } 
//fine 
        $from=($SMTheme->get( 'general','sitename' ))?$SMTheme->get( 'general','sitename' ):get_bloginfo('name');
        if ($error=='') {
            wp_mail($SMTheme->get( 'contactform', 'email' ), 'Message from '.$from, $msg);
            $error=$SMTheme->_( 'emailok' );
            $errorcode='green';
        }
    }        
?>
<?php
    get_header();
?>
<div class='articles'>
    <?php
    the_post(); 
    ?>
        <div class='one-post'>
        <div id="post-<?php the_ID(); ?>" <?php post_class("post-caption"); ?>>
            <?php if (!is_single()&&!is_page()) { ?>
            <h2><a href="<?php the_permalink(); ?>" title="<?php printf( $SMTheme->_( 'permalink' ), the_title_attribute( 'echo=0' ) ); ?>" class='post_ttl'><?php the_title(); ?></a></h2>
            <?php } else { ?>
                <h1><?php the_title(); ?></h1>
            <?php } ?>
        </div>
        <div class='post-body'>
            <?php
                the_content('');
            ?>
        
        <?php if ( $SMTheme->get( 'contactform','address' ) != '' ) {?>
        <div class='googlemap waiting'><div id="map_canvas" style="width: 100%; height: 300px;"></div></div>
        
        <script>jQuery(function(){loadGMap('<?php echo $SMTheme->get( 'contactform','address' )?>', 'map_canvas', 16)});</script>

        <?php } ?>

<?php
    if ($SMTheme->get( 'contactform', 'email' )) {
?>
<form action='' method='POST' class='feedback'>
<h3><?php echo $SMTheme->_( 'feedbackttl' ); ?></h3>
<i><?php echo $SMTheme->_( 'feedbackbefore' ); ?></i>
    <?php
        foreach ($SMTheme->get( 'contactform', 'contactform' ) as $key=>$detail) {
            switch ($detail['type']) {
                case 'text':
                ?>
<p><?php echo $detail['ttl']?>: <?php echo ($detail['req']=='required')?'(*)':''?>
<div class='input'><input type='text' value='' name='<?php echo $key?>'<?php echo ($detail['req']=='required')?" required='true'":''?> /></div>
</p>
                <?php
                break;
                case 'textarea':
                ?>
<p><?php echo $detail['ttl']?>: <?php echo ($detail['req']=='required')?'(*)':''?>
<div class='input'><textarea rows='5' name='<?php echo $key?>'<?php echo ($detail['req']=='required')?" required='true'":''?>></textarea></div>
</p>
                <?php
                break;
            }
        }
    ?>

// parte che ho inserito
<p>
<input name="privacy" type="checkbox" id="privacy" value="1" />
<label for="privacy">Dichiaro di aver letto e accettato <a href="Privacy.html">l'informativa sulla Privacy</a></label></p>
// fine
<?php echo ($error!='')?"<p style='color:".$errorcode."'>".$error."</p>":''?>
<center><input type='submit' class='readmore'  name='submit' value='<?php echo $SMTheme->_( 'send' );?>' /></center>
</form>
<?php } ?>
<?php if ($SMTheme->get( 'contactform','detailttl' ) != '') {?>
<h3><?php echo $SMTheme->get( 'contactform','detailttl' )?></h3>
<?php } ?>
<?php if ($SMTheme->get( 'contactform','text' )) { ?>
<div style='margin-bottom:20px;'>
<?php echo $SMTheme->get( 'contactform','text' )?>
</div>
<?php } 

    $details=$SMTheme->get( 'contactform', 'details' );
    if (!empty($details)) {
?>
<div id='contact'><ul class='contact-details'>
    <?php
        foreach ($details as $key=>$detail) {
        ?>
            <li class='contact<?php echo $key?>'><?php echo $detail['content']?></li>
        <?php
        }
    ?>
</ul></div>
<style>
                    <?php
                        foreach ($SMTheme->get( 'contactform', 'details' ) as $key=>$detail) {
                        ?>
                    ul.contact-details li.contact<?php echo $key?> {
                        background:url(<?php echo $detail['img']?>) left top no-repeat;
                    }
                        <?php
                        }
                    ?>
                </style>
<?php } else { ?>
    <style>
        form.feedback { width:100%;    }
    </style>
<?php    
    }
?>
</div>
        </div>
 </div>
 <script>
    jQuery('.feedback input').each(function(){
        jQuery(this).attr('name','<?php echo $_SESSION['commentinput']; ?>['+jQuery(this).attr('name')+']');
    });
    jQuery('.feedback textarea').each(function(){
        jQuery(this).attr('name','<?php echo $_SESSION['commentinput']; ?>['+jQuery(this).attr('name')+']');
    });
 </script>
<?php
    get_footer();
?>