请问这样是哪里出错了

[sowhatmelon]

root@headless:~/onedrive/91porn_php-master# php detailPage.php http://91porn.com/view_video.php?viewkey=042a30e56c9cd20b075f
PHP Fatal error: Uncaught Error: Class 'DOMDocument' not found in vendor/imangazaliev/didom/src/DiDom/Document.php:64
Stack trace:
#0 detailPage.php(9): DiDom\Document->__construct('http://91porn.c...', true, 'Accept-Language...')
#1 detailPage.php(35): singlePage('http://91porn.c...', '')
#2 {main}
thrown in vendor/imangazaliev/didom/src/DiDom/Document.php on line 64