я не знаю :( просто я уже столько документации перелопатил и ничего не нашел, что грешу на всё подряд.

конфиг nginx.conf:
user webmaster;
worker_processes 3;

events {
worker_connections 1024;
}

http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
access_log /var/log/nginx/access.log;


sendfile on;
keepalive_timeout 1;
tcp_nodelay on;

gzip on;

server {
listen 80;
location / {
root html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
include /etc/nginx/sites-enabled/*;
}

конфиг сервера:
server {
listen 80;
server_name site.ru;

access_log /var/log/site.ru-access.log;
error_log /var/log/site.ru-error.log;

root /home/art/www/site.ru;

location ~* ^.+\.(jpg|jpeg|gif|png|ico|css|js|bmp)$ {
root /home/art/www/site.ru;
}

location ~ /.svn/ {
deny all;
}

if (!-e $request_filename) {
rewrite ^.*$ /index.php last;
}

#location ~ \.php$ {
# fastcgi_pass unix:/tmp/fcgi.sock;
# fastcgi_index index.php;
# fastcgi_param script_FILENAME /home/art/www/site.ru$fastcgi_script_name;
# include fastcgi_params;
#}

location ~ (\.php|/)$ {
expires epoch;
fastcgi_pass unix:/tmp/fcgi.sock;
fastcgi_read_timeout 30;
fastcgi_send_timeout 30;
fastcgi_intercept_errors on;
fastcgi_index index.php;
include fastcgi_params;
}
}