You may not be able to visit this page because of:
Please try one of the following pages:
If difficulties persist, please contact the System Administrator of this site.
SH404SEF : headers were already sent when I got control!
This is not necessarily a sh404sef error. It may have been caused by any of your extensions or even Joomla itself. If there is no error message above this one, providing more details, then you may look inside the error log file of your web server for an indication of what may be breaking things up.
URL=http://www.911-archiv.net/index.php?option=com_kunena&Itemid=542&catid=25&id=473&lang=en&view=topic