Setelah instalasi plugin berhasil.<br />
Saat plugin mau di aktifkan tidak bisa.<br />
Terdapat Error seperti ini.

Warning: require(__DIR__/vendor/autoload.php) [function.require]: failed to open stream: No such file or directory in /home/casekuco/public_html/demopm/wp-content/plugins/plugin-ongkos-kirim/plugin-ongkos-kirim.php on line 21

Warning: require(__DIR__/vendor/autoload.php) [function.require]: failed to open stream: No such file or directory in /home/casekuco/public_html/demopm/wp-content/plugins/plugin-ongkos-kirim/plugin-ongkos-kirim.php on line 21
Fatal error: require() [function.require]: Failed opening required ‘__DIR__/vendor/autoload.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/casekuco/public_html/demopm/wp-content/plugins/plugin-ongkos-kirim/plugin-ongkos-kirim.php on line 21

PHP di hosting yang saya pakai 5.2.17.<br />
Wordpress yang saya pakai 4.3.11

Mohon bantuannya,Terima Kasih