Hi,
I use jbpm inside a web app so my configuration is not the same as for authenticate users in the jbpm console I suppose.
But if you have configure your ldap server you must have all parameters mentioned in the doc :
http://docs.jboss.org/jbpm/v5.4/userguide/ch.human-tasks.html#d0e5256 -> User information retrieved from LDAP server
Regards,