Error trying to update database after module update
The problem you are having is likely either that the RewriteBase is not set in .htaccess, or the base_url is not set in settings.php.  Likely you can bypass the settings problem if you go directly to http://omroepzuidplas.nl/update.php. 

To do database updates you have to be logged in as User 1 (often called admin or super admin, but it could have any user name).