The ltsp.org structure has changed. Under Configuration/LTSP Configuration, the link to the external lts.conf documentation, currently http://www.ltsp.org/documentation/ltsp-3.0-4-en.html#AEN903, should be http://ltsp.mirrors.tds.net/pub/ltsp/docs/ltsp-4.1-en.html#AEN1190 Under Troubleshooting, http://www.ltsp.org/documentation/ should be http://wiki.ltsp.org/twiki/bin/view/Ltsp/Documentation All of the links to ltsp.org in the FAQ section appear to still be working.
Thank you for reporting. Fixed in CVS.