I've using WPMU plugins for a while and I'm really liking

Hi! I've using WPMU plugins for a while and I'm really liking them. I bought a simple VPS instance and I installed Ubuntu with Nginx on it, but now many plugins aren't being installed correctly. For instance, the Ultimate Facebook showed this error upon trying to activate:

Fatal error: Uncaught exception 'Exception' with message 'Facebook needs the CURL PHP extension.' in /var/www/wp-content/plugins/wpmu-dev-facebook/lib/external/base_facebook.php:19 Stack trace: #0 /var/www/wp-content/plugins/wpmu-dev-facebook/lib/external/facebook.php(18): require_once() #1 /var/www/wp-content/plugins/wpmu-dev-facebook/wpmu-dev-facebook.php(105): require_once('/var/www/wp-con...') #2 /var/www/wp-admin/plugins.php(147): include('/var/www/wp-con...') #3 /var/www/wp-admin/plugins.php(149): plugin_sandbox_scrape('wpmu-dev-facebo...') #4 {main} thrown in /var/www/wp-content/plugins/wpmu-dev-facebook/lib/external/base_facebook.php on line 19

Comments Plus actually crashed my installation and I had to ssh to my server and remove it manually. Is it a misconfiguration I've made with my server or an incompatibility with it?

Thanks!!