Help with an error - CMB2 / Inventor plugin (3rd party)

Hello,
I am working on a site using a 3rd party theme called Superlist. It is based on and uses the CMB2 plugin. (https://github.com/WebDevStudios/CMB2) - Basically I am trying to re-order the display of metaboxes based on this instruction: http://inventorwp.com/documentation/helpdesk/code-samples.html#inventor-submission-steps - However when i enter the code in my functions.php file and try to open the submission page this code refers to, I get an error stating: “Metabox configuration is required to have an ID parameter.” - I am at a loss on what else to look for here as i believe i am using the correct ID parameter etc. - The code i am using is this:

add_filter( 'inventor_submission_steps', 'modify_submission_steps', 10, 2 );

function modify_submission_steps( $steps, $post_type ) {
  if ( 'horsesforsale' == $post_type ) {
	        return array(
            'general' => $steps['general'],
            'branding' => $steps['branding'],
            'horseinfo' => $steps['horseinfo'],
            'gallery' => $steps['gallery'],
            'video' => $steps['video'],
            'price' => $steps['price'],
            'location' => $steps['location'],
            'opening-hours' => $steps['opening-hours'],
            'contact' => $steps['contact'],
            'social' => $steps['social'],
        );
    }

      return $steps;
}

I appreciate any help here - this is pretty aggravating as it appears that all should work.
Thank you!
Scott