KnowledgeTree(tm) depends on the following components:

DB Abstraction Layer:
http://phplib.sourceforge.net (LGPL)

Email:
phpmailer - http://phpmailer.sourceforge.net (LGPL)

PHPSniff:
http://phpsniff.sourceforge.net (LGPL)

Mark Round's AuthLDAP class (class.AuthLDAP.php):
http://phpclasses.dknss.com/browse/package/893.html (GPL)

Wouter Verhelt's accept-to-gettext.inc class:
http://www.grep.be/articles/php-accept.php (GPL)