[Plugin: Facebook Comments for WordPress] Error

What is the problem?

Fatal error: Uncaught exception ‘Exception’ with message ‘Facebook needs the CURL PHP extension.’ in xxx/htdocs/wp-content/plugins/facebook-comments-for-wordpress/scripts/facebook.php:4 Stack trace: #0 xxx/htdocs/wp-content/plugins/facebook-comments-for-wordpress/facebook-comments.php(34): require_once() #1 xxx/htdocs/wp-admin/plugins.php(149): include(‘/xxx…’) #2 /xxx/htdocs/wp-admin/plugins.php(151): plugin_sandbox_scrape(‘facebook-commen…’) #3 {main} thrown in /xxx/htdocs/wp-content/plugins/facebook-comments-for-wordpress/scripts/facebook.php on line 4