samrods on "[Theme: Spun] Page template with right sidebar"

Hi everyone. I am trying to do a page template with a sidebar, so I can decide if i want to use a sidebar in a per-page basis. This was suggested by KelleyKavanaugh, in this post: http://wordpress.org/support/topic/page-with-sidebar-on-right-side?replies=3.
I succeeded in creating a page with 70% width.
But, when i tried to create a functions.php on my spun-child page, I've got only errors.
I created a functions.php trying several different instructions I saw in different articles, on how to assign a new sidebar, but always got errors. Here is one example:

<?php
// Widget Areas //
if ( function_exists('register_sidebars') ) {
register_sidebar( array(
    'name' => __( 'Right Sidebar', 'unique' ),
    'id' => 'sidebar-4',
    'description' => __( 'The right sidebar widget area for pages.', 'unique' ),
) );
   register_sidebar( array(
    'name' => __( 'Left Sidebar', 'unique' ),
    'id' => 'sidebar-5',
    'description' => __( 'The left sidebar widget area for pages.', 'unique' ),
) );
}
?>

The error it returns to me is:

Fatal error: Cannot redeclare _verify_isactivate_widgets() (previously declared in /wp-content/themes/spun-child/functions.php:20) in /wp-content/themes/spun/functions.php on line 367

My spun version is 2.0.2

What could be wrong here?

Thanks for your help.