Support for WordPress Car Dealer

I receive the following error when uploading a picture: “Fatal error: Call to undefine function get_post_thumbnail_id()”

Please create or edit the file wp-content/your-theme/functions.php and add the following:

<?php add_theme_support('post-thumbnails'); ?>

I receive the following error when installing the plugin: “The plugin does not have a valid header.”

Please upload the plugin using FTP, do not use the native WordPress plugin uploader.

$29

Philo01

Last Update	12 September 14
Created	21 December 10
High Resolution	No
Compatible Browsers	IE6, IE7, IE8, Safari, Opera
Files Included	JavaScript JS, HTML, CSS, PHP
Software Version	WordPress 4.0, WordPress 3.9, WordPress 3.8, WordPress 3.7, WordPress 3.6, WordPress 3.5, WordPress 3.4, WordPress 3.3, WordPress 3.2, WordPress 3.1, WordPress 3.0
Tags	2 build in sliders, car, dealer, native post type & taxonomies, over 35 settings