W3 Total Cache: Minify not working?

I followed the instructions here regarding configuring W3 Total Cache, and I followed the instructions precisely. I also used rtCamp’s instructions on setting up Nginx and PHP-FPM.

When I tried to manually add CSS and JS files in W3 Total Cache’s Minify feature, a single “minified” file was created, but it’s completely blank. Any idea on what I might be doing wrong?

server {  
	server_name dcturano.com www.dcturano.com;  

	access_log /var/log/nginx/dcturano.access.log;  
	error_log /var/log/nginx/dcturano.error.log debug;  

	root /var/www/dcturano/htdocs;  
	index index.php;  

	# dcturano SSL directives  

		listen 443 ssl;  

		ssl_session_cache builtin:1000 shared:SSL:10m;  
		ssl_session_timeout 5m;  

		ssl_stapling on;  
		ssl_stapling_verify on;  
		resolver 8.8.8.8;  

		ssl_protocols TLSv1 TLSv1.1 TLSv1.2;  
		ssl_prefer_server_ciphers on;  
		ssl_ciphers 'ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:ECDHE-RSA-RC4-SHA:ECDHE-ECDSA-RC4-SHA:RC4-SHA:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!3DES:!MD5:!PSK';  

		add_header Strict-Transport-Security max-age=31536000;  

	# End dcturano SSL directives  

	set $cache_uri $request_uri;  

	if ($request_method = POST) {  
		set $cache_uri 'null cache';  
	}  
	if ($query_string != "") {  
		set $cache_uri 'null cache';  
	}  

	if ($request_uri ~* "(/wp-admin/|/xmlrpc.php|/wp-(app|cron|login|register|mail).php|wp-.*.php|/feed/|index.php|wp-comments-popup.php|wp-links-opml.php|wp-locations.php|sitemap(_index)?.xml|[a-z0-9_-]+-sitemap([0-9]+)?.xml)") {  
		set $cache_uri 'null cache';  
	}  

	if ($http_cookie ~* "comment_author|wordpress_[a-f0-9]+|wp-postpass|wordpress_logged_in") {  
		set $cache_uri 'null cache';  
	}  

	location / {  
		try_files /stack/cache/page_enhanced/${host}${cache_uri}_index.html $uri $uri/ /index.php?$args ;  
	}  

	location ~ ^/stack/cache/minify/[^/]+/(.*)$ {  
		try_files $uri /stack/plugins/w3-total-cache/pub/minify.php?file=$1;  
	}  

	location = /favicon.ico { log_not_found off; access_log off; }  
	location = /robots.txt  { log_not_found off; access_log off; }  

	location ~ .php$ {  
		fastcgi_pass unix:/var/run/php5-fpm.sock;  
		include fastcgi_params;  
		try_files $uri /index.php;  
	}  

	location ~* .(ogg|ogv|svg|svgz|eot|otf|woff|mp4|ttf|css|rss|atom|js|jpg|jpeg|gif|png|ico|zip|tgz|gz|rar|bz2|doc|xls|exe|ppt|tar|mid|midi|wav|bmp|rtf)$ {  
		expires max; log_not_found off; access_log off;  
	}  
}