devise.rb and error

devise.rb

# Devise.rb
Devise.setup do |config|
  # ==> LDAP Configuration
  config.ldap_logger = true
  config.ldap_create_user = true
  #config.ldap_update_password = true
  #config.ldap_config = "#{Rails.root}/config/ldap.yml"
  #config.ldap_check_group_membership = true
  config.ldap_check_attributes = true
  config.ldap_use_admin_to_bind = true
  #config.ldap_ad_group_check = true

# Error

devise_ldap_authenticatable (0.6.1) lib/devise_ldap_authenticatable/ldap_adapter.rb:210:in `has_required_attribute?'
devise_ldap_authenticatable (0.6.1) lib/devise_ldap_authenticatable/ldap_adapter.rb:157:in `authorized?'
devise_ldap_authenticatable (0.6.1) lib/devise_ldap_authenticatable/ldap_adapter.rb:14:in `valid_credentials?'
devise_ldap_authenticatable (0.6.1) lib/devise_ldap_authenticatable/model.rb:45:in `valid_ldap_authentication?'
org/jruby/RubyKernel.java:2080:in `send'