Bad Request wp e-commerce

if( isset($wp_query->query_vars['wpsc_product_category']) && !isset($wp_query->query_vars['wpsc-product'])){
        $query->query_vars['wpsc_product_category'] = $wp_query->query_vars['wpsc_product_category'];
        $query->query_vars['taxonomy'] = $wp_query->query_vars['taxonomy'];
        $query->query_vars['term'] = $wp_query->query_vars['term'];
    }elseif( '' != ($default_category = get_option('wpsc_default_category')) && !isset($wp_query->query_vars['wpsc-product'])){
        $default_term = get_term($default_category,'wpsc_product_category');
        if(!empty($default_term) && empty($wp_query->query_vars['category_name'])){
            $query->query_vars['taxonomy'] = 'wpsc_product_category';
            $query->query_vars['term'] = $default_term->slug;
            $query->is_tax = true;
        }elseif(isset($wp_query->query_vars['name']) && $wp_query->is_404 && $wp_query->query_vars['category_name'] != $prod_page->post_name){
            unset( $query->query_vars['taxonomy'] );
            unset( $query->query_vars['term'] );
            $query->query_vars['wpsc-product'] = $wp_query->query_vars['name'];
            $query->query_vars['name'] = $wp_query->query_vars['name'];


        }else{
            $query->is_tax = true;
            $term =    get_term_by('slug',$wp_query->query_vars['name'], 'wpsc_product_category' );
            if(!empty($term)){
                $query->query_vars['taxonomy'] = 'wpsc_product_category';
                $query->query_vars['wpsc_product_category__in'] = array($term->term_taxonomy_id);
                $query->query_vars['wpsc_product_category'] = $wp_query->query_vars['name'];
                $query->query_vars['term'] = $wp_query->query_vars['name'];
            }elseif(is_numeric($default_category)){
                $query->query_vars['taxonomy'] = 'wpsc_product_category';
            }else{
                $query->is_tax = false;
            }
        }
    }