The file name is ad_auth_settings.properties and not auth_settings.properties (there is already a comment stating that in the documentation).
The content of the file, if you still can't find the right one
SERVERS=<AD Server>
ADMINDN=<Administrator DN>
ADMINPWD=<Administrator Password>
BASEDN=<Base DN>
KEYSTOREPWD=<Key store password>
#SSL=TRUE
#ADMINPWD={ENC}Hk2JRrjEMRp2ngjgUdRYNP6Y24YUA/Pi
#KEYSTOREPWD={ENC}ySiOwUQDtkB3z/tbo9QQWlzNlHf5TP+o
#SEARCHFILTER=CN=%s
#SEARCHFILTER=(&(objectCategory=person)(objectClass=user)(cn=%s))
#SEARCHFILTER=(&(objectCategory=person)(objectClass=user)(sAMAccountName=%s))
#java -cp <IAM_IM.EAR>/user_console.war/WEB-INF/lib/user_console.jar com.netegrity.webapp.authentication.ad.EncTicket <password>