W3 Total Cache isn't caching pages (Nginx, PHP 5.6 FPM and MySQL)

Hi everyone. I’m using Nginx, PHP 5.6 FPM and MySQL on Ubuntu Server 14.04. I installed the W3 Total Cache plugin and enabled the enhanced disk page cache. However,it doesn’t seem to be caching anything, and the directory wp-content/cache/page_enhanced doesn’t exist.

I’ve included in my Nginx configuration the rewrite rules. I feel like I’ve tried everything, though obviously I missed something. Anyone know what I can try to get this working?

Here’s my Nginx virtual host configuration:

server {

	listen	80;

	client_max_body_size 10M;

	root /home/james/www;
	index index.php index.html index.htm;

	server_name test.jeffcolemanwrites.local;

	include /home/james/www/nginx.conf;

	location / {
		try_files $uri $uri/ /index.php?q=$uri&$args;
	}

	error_page 404 /404.html;

	error_page 500 502 503 504 /50x.html;
	location = /50x.html {
		root /usr/share/nginx/www;
	}

	# pass the PHP scripts to FastCGI server listening on the php-fpm socket
	location ~ \.php$ {
		try_files $uri =404;
		fastcgi_pass unix:/var/run/php5-fpm.sock;
		fastcgi_index index.php;
		fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
		include fastcgi_params;
	}
}

include /home/james/www/nginx.conf contains the rewrite rules installed by W3 Total Cache.