OK,

I don't know ruby but if all of the proper attributes are not given in ldap authentication in settings (Firstname, lastname, and email are stated as optional but are not actually) then the failure message causes a crash.

The ill formed error message seems to come from on line 114 if user.rb

         logger.error("User '#{onthefly.login}' found in LDAP but could not be\
 created (#{onthefly.errors.full_messages.join(', ')})") if logger

sh-3.2$ RAILS_ENV=development ruby script/about
GLoc v1.1 running in development mode. Strings can be modified at runtime.
About your application's environment
Ruby version 1.8.6 (universal-darwin9.0)
RubyGems version 1.2.0
Rails version 2.0.2
Active Record version 2.0.2
Action Pack version 2.0.2
Active Resource version 2.0.2
Action Mailer version 2.0.2
Active Support version 2.0.2
Edge Rails revision rel_2-0-2
Application root /Library/WebServer/Documents/redmine
Environment development
Database adapter mysql
Database schema version 92

Processing AccountController#login (for 127.0.0.1 at 2008-09-19 14:39:54) [POST]
Session ID: 1fe52ef1f619b533a66e7569d58f5f52
Parameters: {"action"=>"login", "username"=>"foo", "bar"=>"account", "password"=>"[FILTERED]", "login"=>"Login »"}
Setting Columns (0.001288) SHOW FIELDS FROM settings
SQL (0.000091) SELECT max(updated_on) AS max_updated_on FROM settings
SQL (0.000531) SHOW TABLES
User Columns (0.001307) SHOW FIELDS FROM users
SQL (0.000588) SHOW TABLES
Project Columns (0.001238) SHOW FIELDS FROM projects
SQL (0.000443) SHOW TABLES
Issue Columns (0.001434) SHOW FIELDS FROM issues
SQL (0.000395) SHOW TABLES
SQL (0.000576) SHOW TABLES
SQL (0.000722) SHOW TABLES
AnonymousUser Columns (0.001611) SHOW FIELDS FROM users
AnonymousUser Load (0.000211) SELECT * FROM users WHERE ( (users.type = 'AnonymousUser' ) ) LIMIT 1
User Load (0.000310) SELECT * FROM users WHERE (login='foo') LIMIT 1
SQL (0.000498) SHOW TABLES
AuthSource Load (0.000215) SELECT * FROM auth_sources WHERE (onthefly_register=1)
AuthSource Columns (0.001333) SHOW FIELDS FROM auth_sources
AuthSourceLdap Columns (0.001376) SHOW FIELDS FROM auth_sources
Authenticating 'tegtmeye' against 'localhost'
DN found for tegtmeye: uid=foo,cn=users,dc=some,dc=long,dc=long,dc=domain
Authentication successful for 'tegtmeye'
Setting Load (0.000104) SELECT * FROM settings WHERE (settings.name = 'default_language') LIMIT 1
SQL (0.000059) BEGIN
User Load (0.000291) SELECT * FROM users WHERE (users.login = 'foo') LIMIT 1
SQL (0.000054) COMMIT

TypeError (can't convert Array into String):
/vendor/plugins/gloc-1.1.0/lib/gloc-rails.rb:171:in +'
/vendor/plugins/gloc-1.1.0/lib/gloc-rails.rb:171:infull_messages'
/vendor/plugins/gloc-1.1.0/lib/gloc-rails.rb:165:in each'
/vendor/plugins/gloc-1.1.0/lib/gloc-rails.rb:165:infull_messages'
/vendor/plugins/gloc-1.1.0/lib/gloc-rails.rb:164:in each_key'
/vendor/plugins/gloc-1.1.0/lib/gloc-rails.rb:164:infull_messages'
/app/models/user.rb:113:in try_to_login'
/app/controllers/account_controller.rb:46:inlogin'
/vendor/rails/actionpack/lib/action_controller/base.rb:1158:in send'
/vendor/rails/actionpack/lib/action_controller/base.rb:1158:inperform_action_without_filters'
/vendor/rails/actionpack/lib/action_controller/filters.rb:697:in call_filters'
/vendor/rails/actionpack/lib/action_controller/filters.rb:689:inperform_action_without_benchmark'
/vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in perform_action_without_rescue'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/benchmark.rb:293:inmeasure'
/vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in perform_action_without_rescue'
/vendor/rails/actionpack/lib/action_controller/rescue.rb:199:inperform_action_without_caching'
/vendor/rails/actionpack/lib/action_controller/caching.rb:678:in perform_action'
/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:33:incache'
/vendor/rails/activerecord/lib/active_record/query_cache.rb:8:in cache'
/vendor/rails/actionpack/lib/action_controller/caching.rb:677:inperform_action'
/vendor/rails/actionpack/lib/action_controller/base.rb:524:in send'
/vendor/rails/actionpack/lib/action_controller/base.rb:524:inprocess_without_filters'
/vendor/rails/actionpack/lib/action_controller/filters.rb:685:in process_without_session_management_support'
/vendor/rails/actionpack/lib/action_controller/session_management.rb:123:inprocess'
/vendor/rails/actionpack/lib/action_controller/base.rb:388:in process'
/vendor/rails/actionpack/lib/action_controller/dispatcher.rb:171:inhandle_request'
/vendor/rails/actionpack/lib/action_controller/dispatcher.rb:115:in dispatch'
/vendor/rails/actionpack/lib/action_controller/dispatcher.rb:126:indispatch_cgi'
/vendor/rails/actionpack/lib/action_controller/dispatcher.rb:9:in dispatch'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:inprocess'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in synchronize'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:inprocess'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in process_client'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:ineach'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in process_client'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:inrun'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in initialize'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:innew'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:ininitialize'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in new'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:inrun'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:ineach'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in run'
/usr/bin/mongrel_rails_server:131:inrun'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run'
/usr/bin/mongrel_rails_server:256

Rendering /Library/WebServer/Documents/redmine/vendor/rails/actionpack/lib/action_controller/templates/rescues/layout.erb (internal_server_error)