Here there're the wiki entry for it
http://wiki.openkm.com/index.php/Active ... OpenKM_5.1
Only as an advice configure ldap is never easy at least you need couple of hours for doing it. Be pacient, and step by step, first login ( xml file ) and after it you can try with configuration parameters. Remember each time you change xml file ( each try ) you must restart server to take any effect.