Config seems ok

templates/etc/nginx/sites-available/_backuppc.j2

@@ -25,7 +25,7 @@
 {% block template_upstream_location %}
 	location ~ \.cgi$ {
 		gzip off;
-		include /etc/nginx/fastcgi_params;
+		include {{ nginx_etc_dir }}/fastcgi_params;
 		fastcgi_pass unix:/var/run/fcgiwrap.socket;
 		fastcgi_index BackupPC_Admin;
 		fastcgi_param SCRIPT_FILENAME /usr/share/backuppc/cgi-bin$fastcgi_script_name;

templates/etc/nginx/sites-available/_proxy.j2

@@ -7,7 +7,7 @@
 {% endblock %}
 
 {% block template_try_files %}
-		include /etc/nginx/proxy_params;
+		include {{ nginx_etc_dir }}/proxy_params;
 		proxy_pass http://{{ item.upstream_name }};
 {% if item.proxy_params is defined and item.proxy_params is iterable %}
 {% for param in item.proxy_params %}