server {
    listen 8080;
    server_name task.server.ank;

    location /task {
        index index.php;
        alias /srv/www/task;
        try_files $uri $uri/ index.php$is_args$args;
    }

    location ~  ^/task(.+\.php)$ { ### This location block was the solution
        alias /srv/www/task;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_index index.php;
        try_files $uri /index.php =404;
        include /etc/nginx/fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$1;
# fastcgi_pass unix:/var/run/php5-fpm.sock;
        fastcgi_pass 127.0.0.1:9000;
    }
}