I receive an error message when this plugin is enabled

When I enable the Contact Widget, I get the following error:

Notice: wp_enqueue_script was called incorrectly. Scripts and styles should not be registered or enqueued until the wp_enqueue_scripts, admin_enqueue_scripts, or init hooks. Please see Debugging in WordPress for more information. (This message was added in version 3.3.) in /var/www/nes/wp-includes/functions.php on line 2962