Custom widget areas failing in Pro

When I was working with a child of the free Startup theme, I successfully created two new widget areas in the header. Now I have bought StartupPro and tried to transfer my relevant code to the startuppro-child theme, but the widget areas aren’t working. What is different between regular and Pro that might affect this?

The code changes I do are as follows. I add a functions.php with the following:

<?php
add_action( 'widgets_init', 'startupchild_widgets_init' );
function startupchild_widgets_init() {
  register_sidebar( array (
  'name' => __( 'Banner Center Widget Area', 'startup' ),
  'id' => 'bannercenter-widget-area',
  'before_widget' => '<div id="%1$s">',
  'after_widget' => "</div>",
  'before_title' => '<h3 class="widget-title">',
  'after_title' => '</h3>',
  ) );
  register_sidebar( array (
  'name' => __( 'Banner Right Widget Area', 'startup' ),
  'id' => 'bannerright-widget-area',
  'before_widget' => '<div id="%1$s">',
  'after_widget' => "</div>",
  'before_title' => '<h3 class="widget-title">',
  'after_title' => '</h3>',
  ) );
}
?>

Then I copy header.php from the parent theme to the child, and edit it to add this code between the site description and the nav menu:

<?php if ( is_active_sidebar('bannerright-widget-area') ) : ?>
<div id="bannerright" class="widget-area">
<?php dynamic_sidebar('bannerright-widget-area'); ?>
</div>
<?php endif; ?>
<?php if ( is_active_sidebar('bannercenter-widget-area') ) : ?>
<div id="bannercenter" class="widget-area">
<?php dynamic_sidebar('bannercenter-widget-area'); ?>
</div>
<?php endif; ?>