无法安装框架

无法安装框架 到第二部就404了 /index.php/index/step2 下载以后没有修改文件，是nginx配置有问题还是框架本身有问题？

nginx配置文件如下

server {
        listen  80;
        root /home/www/wzblog/;
        access_log  logs/nginx.access.log  main;
        error_log  logs/nginx.error.log;

        location / {

            index index.php index.html index.htm;

        }

        error_page   500 502 503 504 /50x.html;
        location = /50x.html {
        }

        location ~ ^/(images|javascript|js|css|flash|media|static)/ {

            expires 30d;
        }

        location ~ .php$ {
            fastcgi_pass  unix:/tmp/php-cgi.sock;
            fastcgi_index index.php;
            fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
            include fastcgi_params;
        }
}