Link error when opening in popup

Would they know where the error is located?

That's how it works:

   public function upme_favorite_posts_list($atts){
    global $post,$wpdb,$upme_options;

    extract( shortcode_atts( array(
        'number_of_posts'   => 200 ,
        'featured_image' => 'no',
        'user_id' => 'no',
      ), $atts ) );

    $content = '';

    if($user_id != 'no'){
        $user_id = (int) $user_id;
        if( $user_id == '0' ){
            if(is_user_logged_in()){
                $user_id = get_current_user_id(); 

                $sql  = $wpdb->prepare( "SELECT upf.*,p.post_excerpt,p.guid FROM {$wpdb->prefix}upme_post_features as upf inner join  $wpdb->posts as p on p.ID = upf.post_id  WHERE upf.favorite_status = %d AND upf.user_id = %d", 1 , $user_id );
            }else{
                return;
            }
        }else{
            $sql  = $wpdb->prepare( "SELECT upf.*,p.post_excerpt,p.guid FROM {$wpdb->prefix}upme_post_features as upf inner join  $wpdb->posts as p on p.ID = upf.post_id  WHERE upf.favorite_status = %d AND upf.user_id = %d", 1 , $user_id );
        }

        $result = $wpdb->get_results($sql);
        if($result){

            $featured_enabled_types = (array) $upme_options->upme_settings['featured_image_enabled_types'];
            $featured_image_setting_status = in_array('favorite',$featured_enabled_types);  
            $featured_image_status = ($featured_image == 'no' || $featured_image_setting_status);

            $content .= '<div class="upme-main upme-main-">';
            foreach($result as $row){


                if($featured_image_status){

                    $image_attributes = wp_get_attachment_image_src(get_post_thumbnail_id($row->post_id), 'thumbnail');
                    $image_src = upme_url . 'img/default-post-thumbnail.png';
                    if($upme_options->upme_settings['favorite_default_featured_image'] != ''){
                        $image_src = $upme_options->upme_settings['favorite_default_featured_image'];
                    }
                    if (is_array($image_attributes) && ('' != $image_attributes[0])) {
                        $image_src = $image_attributes[0];
                    }

                    $content .= '<div class="upme-main upme-main-">


                                    <span>

  <a target="_blank" href="'.$row->guid.'">'.$row->post_excerpt.'</a>
                                    </span>

                            </div>';

                }else{
                    $content .= '<div class="upme-main upme-main-">


                                    <span>
                                    <a target="_blank" href="'.$row>guid.'">'.$row->post_excerpt.'</a>
                                    </span>

                            </div>';
                }



            }
            $content .= '</div><div class="upme-clear"></div>';
        }
  //            echo "<pre>";print_r($result);exit;
    }

    return $content;
}

I am replacing this line:

     <a target="iframe1" href="'.$row->guid.'">'.$row->post_excerpt.'</a>

for this:

<a href="javascript: void(0)" onclick="window.open('.$row->guid.','_blank','width=900,height=300');">'.$row->post_excerpt.'</a>

but I throw error and I can not open wordpress .. Thank you very much!