Activating the Plugin

Hi,

I have installed the Ultimate Facebook on Multisite setup. When i try to Network activate the plugin, i get this:

Fatal error: Uncaught exception 'Exception' with message 'Facebook needs the CURL PHP extension.' in blog/wp-content/plugins/wpmu-dev-facebook/lib/external/base_facebook.php:19 Stack trace: #0 blog/wp-content/plugins/wpmu-dev-facebook/lib/external/facebook.php(18): require_once() #1 blog/wp-content/plugins/wpmu-dev-facebook/wpmu-dev-facebook.php(102): require_once('/production/fd_...') #2 blog/wp-admin/plugins.php(142): include('/production/fd_...') #3 blog/wp-admin/plugins.php(144): plugin_sandbox_scrape('wpmu-dev-facebo...') #4 {main} thrown in blog/wp-content/plugins/wpmu-dev-facebook/lib/external/base_facebook.php on line 19

Do you know what is the problem?

Thanks