Bulk_Upgrader_Skin::error( string|WP_Error $error )

	public function error($error) {
		if ( is_string($error) && isset( $this->upgrader->strings[$error] ) )
			$this->error = $this->upgrader->strings[$error];

		if ( is_wp_error($error) ) {
			$messages = array();
			foreach ( $error->get_error_messages() as $emessage ) {
				if ( $error->get_error_data() && is_string( $error->get_error_data() ) )
					$messages[] = $emessage . ' ' . esc_html( strip_tags( $error->get_error_data() ) );
				else
					$messages[] = $emessage;
			}
			$this->error = implode(', ', $messages);
		}
		echo '<script type="text/javascript">jQuery(\'.waiting-' . esc_js($this->upgrader->update_current) . '\').hide();</script>';
	}