try this steps.
check this value:
$ldapservers->SetValue($i,'server','base',array(''));
change it to for "example.com"
$ldapservers->SetValue($i,'server','base',array('dc=example,dc=com'));
check this value:
$ldapservers->SetValue($i,'login','dn',' ');
chang it to
$ldapservers->SetValue($i,'login','dn','cn=Manager,dc=example,dc=com');
Note: You have to tweak the config.php reading the comments and make the phpldapadmin connection secure with apache+SSL
Here is my config.php if u want to use. Just search & replace dc=example,dc=com with your own domain name
http://d.turboupload.com/d/155737/config.php.html