Hi,
I don't know another way to access the backend. So I use
www.hiphopgemeenschap.nl/administrator. And there I'm getting the error: "Your registered domain does not match. You will obtain the non-paid version of JoomSEF when launching upgrade from ARTIO Server."
The redirection is by the joomla core itself. Using the error.php from my template to redirect to my own 404 page, instead of the default 404 page.
The problem I'm experiencing is that without Joomsef activated, the filter and pagignation works flawless. With Joomsef activated it's giving me the error page.