I dropped a note to brett [at] ... I'm just a moderator and can't do anything. But it looks like some kind of database injection:
 
<META HTTP-EQUIV="Refresh"
      CONTENT="0; URL=http://xsaimex.mybrute.com/"><br />
<b>Warning</b>:  include_once(includes/VBSEO_VB_CONFIG) [<a href='function.include-once'>function.include-once</a>]: failed to open stream: No such file or directory in <b>/var/www/vhosts/roundcubeforum.net/httpdocs/vbseo.php ...........