Subpages return 404 error [closed]

I set permanent link as http://site.com/%postname%/.
I’m talking about this type of pages: http://codex.wordpress.org/Pages_Screen.
All first level pages work fine. But subpages don’t.

For the first level page I get url like this: http://site.com/page/.
For the second level page – http://site.com/page/subpage/.

If I use permanent link http://site.com/?p=123 or http://site.com/2012/02/29/sample-post/, subpage works fine then.

How does make it work with http://site.com/%postname%/ mask?

Added:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

Update:

I found the reason. It is a post_type field in the wp_posts. But I cannot find out where this field is saved?

You’re wanting to use “Pretty Permalinks” and in order to do so you need to have some form of rewrite documentation present. The easiest and most common is a .htaccess file to hold the rewrite rules.

Do you have an .htaccess present for the site?

If you do not, you can reference the WordPress Codex here: http://codex.wordpress.org/Using_Permalinks#Where.27s_my_.htaccess_file.3F