if (function_exists('register_sidebar')) {
     register_sidebar(array(
         'name' => 'Subscribe Pop-up Wording',
         'id' => 'subscribe-popup',
         'description' => 'This is the content for the subscribe pop-up',
         'before_widget' => '
',         'after_widget' => '
',
         'before_title' => '',         'after_title' => '
'
     ));
 }

<?php if (!function_exists('dynamic_sidebar') || !dynamic_sidebar('Subscribe Pop-up') ) : endif; ?>