The URL in /etc/X11/applnk/Documentation/Linux Community/howto.desktop points to "/usr/share/doc/HOWTO/" which makes no sense! It should be changed to /usr/share/doc/HOWTO/other-formats/html/HOWTO-INDEX/index.html
This was intentional, due to the unpredictability of the content we get from the LDP mirror. By directing people to the directory listings, we can ensure that people see everything that is available, and don't get 404s when a document is not available or has been moved/renamed. An HTML-only presentation would be nice, but we feel that if we have to choose between nice and reliable, we'll pick reliable every time... :-)