CentOS 6.4 64-bit
Apache 2.4.6
PHP-FPM 5.5.4

Homepage from root loads fine http://csillamvilag.com
But all other pages return 404 (CMS is WordPress).
I am also able to access and log into WordPress backend.

Additionally, Menalto Gallery 3 seems to be loading ok http://csillamvilag.com/kepek/ but all OpenCart pages return 404 http://csillamvilag.com/shop/ or http://csillamvilag.com/shop/hu/

Apache is running as user apache.
All relevant WordPress and OpenCart files are owned by user apache.

I have a suspicion that it might be a rewrite issue, but I checked .htaccess for both WordPress and OpenCart, and they look ok. e.g. WordPress/root .htaccess is:

# 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>