redmineがLDAPにつながらない

redmineLDAP認証の設定を行った時,ログに以下が表示されうまく認証できない.

  TypeError (can't convert Net::LDAP::LdapError into String):
  app/models/auth_source_ldap.rb:43:in `rescue in authenticate'
  app/models/auth_source_ldap.rb:35:in `authenticate'
  app/models/user.rb:109:in `try_to_login'
  app/controllers/account_controller.rb:147:in `password_authentication'
  app/controllers/account_controller.rb:142:in `authenticate_user'
  app/controllers/account_controller.rb:30:in `login'
  :10:in `synchronize'
  passenger (3.0.1) lib/phusion_passenger/rack/request_handler.rb:96:in `process_request'
  passenger (3.0.1) lib/phusion_passenger/abstract_request_handler.rb:513:in `accept_and_process_next_request'
  passenger (3.0.1) lib/phusion_passenger/abstract_request_handler.rb:274:in `main_loop'
  passenger (3.0.1) lib/phusion_passenger/classic_rails/application_spawner.rb:321:in `start_request_handler'
  passenger (3.0.1) lib/phusion_passenger/classic_rails/application_spawner.rb:275:in `block in handle_spawn_application'
  passenger (3.0.1) lib/phusion_passenger/utils.rb:479:in `safe_fork'
  passenger (3.0.1) lib/phusion_passenger/classic_rails/application_spawner.rb:270:in `handle_spawn_application'
  passenger (3.0.1) lib/phusion_passenger/abstract_server.rb:357:in `server_main_loop'
  passenger (3.0.1) lib/phusion_passenger/abstract_server.rb:206:in `start_synchronously'
  passenger (3.0.1) lib/phusion_passenger/abstract_server.rb:180:in `start'
  passenger (3.0.1) lib/phusion_passenger/classic_rails/application_spawner.rb:149:in `start'
  passenger (3.0.1) lib/phusion_passenger/spawn_manager.rb:219:in `block (2 levels) in spawn_rails_application'
  passenger (3.0.1) lib/phusion_passenger/abstract_server_collection.rb:132:in `lookup_or_add'
  passenger (3.0.1) lib/phusion_passenger/spawn_manager.rb:214:in `block in spawn_rails_application'
  passenger (3.0.1) lib/phusion_passenger/abstract_server_collection.rb:82:in `block in synchronize'
  :10:in `synchronize'
  passenger (3.0.1) lib/phusion_passenger/abstract_server_collection.rb:79:in `synchronize'
  passenger (3.0.1) lib/phusion_passenger/spawn_manager.rb:213:in `spawn_rails_application'
  passenger (3.0.1) lib/phusion_passenger/spawn_manager.rb:132:in `spawn_application'
  passenger (3.0.1) lib/phusion_passenger/spawn_manager.rb:275:in `handle_spawn_application'
  passenger (3.0.1) lib/phusion_passenger/abstract_server.rb:357:in `server_main_loop'
  passenger (3.0.1) lib/phusion_passenger/abstract_server.rb:206:in `start_synchronously'
  passenger (3.0.1) helper-scripts/passenger-spawn-server:99:in `'

ruby1.9系だと動かないみたいなので,1.8.6 か 1.8.7を使用すると動きました. http://www.redmine.org/issues/4824