If you have the Page Header Add-on installed, deactivate it. Then try this function:
add_action( 'wp','generate_remove_page_header' );
function generate_remove_page_header() {
remove_action('generate_after_header','generate_featured_page_header', 10);
remove_action('generate_before_content','generate_featured_page_header_inside_single', 10);
}