我已将系统从Ubuntu 10.04升级到Ubuntu 12.04。在此过程中，redmine已经升级。在10.04我使用PPA ppa：ondrej / redmine，在12.04我使用的是Ubuntu股票版本（1.3.2 + dfsg1-1ubuntu1）
大多数问题仍然存在，但我遇到一个特定问题的问题：它没有列出，直接访问它（我有链接标记）在日志中抛出错误：
Processing IssuesController#show (for AA.BB.CC.DD at 2012-10-19 11:19:24) [GET]
Parameters: {"action"=>"show", "controller"=>"issues", "id"=>"93"}
ActiveRecord::SubclassNotFound (The single-table inheritance mechanism failed to locate the subclass: 'WorkflowTransition'. This error is raised because the column 'type' is reserved for storing the class in case of inheritance. Please rename this column if you didn't intend it to be used for storing the inheritance class or overwrite Workflow.inheritance_column to use another column for that information.):
/usr/lib/ruby/vendor_ruby/active_record/base.rb:1671:in `instantiate'
/usr/lib/ruby/vendor_ruby/active_record/base.rb:665:in `find_by_sql'
/usr/lib/ruby/vendor_ruby/active_record/base.rb:665:in `collect!'
/usr/lib/ruby/vendor_ruby/active_record/base.rb:665:in `find_by_sql'
/usr/lib/ruby/vendor_ruby/active_record/base.rb:1582:in `find_every'
/usr/lib/ruby/vendor_ruby/active_record/base.rb:619:in `find'
/usr/lib/ruby/vendor_ruby/active_record/associations/association_collection.rb:60:in `find'
app/models/issue_status.rb:78:in `find_new_statuses_allowed_to'
/usr/lib/ruby/vendor_ruby/active_record/associations/association_proxy.rb:215:in `send'
/usr/lib/ruby/vendor_ruby/active_record/associations/association_proxy.rb:215:in `method_missing'
app/models/issue.rb:471:in `new_statuses_allowed_to'
app/controllers/issues_controller.rb:122:in `show'
/usr/lib/ruby/vendor_ruby/action_controller/base.rb:1333:in `send'
/usr/lib/ruby/vendor_ruby/action_controller/base.rb:1333:in `perform_action_without_filters'
/usr/lib/ruby/vendor_ruby/action_controller/filters.rb:617:in `call_filters'
/usr/lib/ruby/vendor_ruby/action_controller/filters.rb:610:in `perform_action_without_benchmark'
/usr/lib/ruby/vendor_ruby/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/usr/lib/ruby/vendor_ruby/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/usr/lib/ruby/vendor_ruby/action_controller/rescue.rb:160:in `perform_action_without_flash'
/usr/lib/ruby/vendor_ruby/action_controller/flash.rb:151:in `perform_action'
/usr/lib/ruby/vendor_ruby/action_controller/base.rb:532:in `send'
/usr/lib/ruby/vendor_ruby/action_controller/base.rb:532:in `process_without_filters'
/usr/lib/ruby/vendor_ruby/action_controller/filters.rb:606:in `process'
/usr/lib/ruby/vendor_ruby/action_controller/base.rb:391:in `process'
/usr/lib/ruby/vendor_ruby/action_controller/base.rb:386:in `call'
/usr/lib/ruby/vendor_ruby/action_controller/routing/route_set.rb:438:in `call'
/usr/lib/ruby/vendor_ruby/action_controller/dispatcher.rb:87:in `dispatch'
/usr/lib/ruby/vendor_ruby/action_controller/dispatcher.rb:121:in `_call'
/usr/lib/ruby/vendor_ruby/action_controller/dispatcher.rb:130:in `build_middleware_stack'
/usr/lib/ruby/vendor_ruby/active_record/query_cache.rb:29:in `call'
/usr/lib/ruby/vendor_ruby/active_record/query_cache.rb:29:in `call'
/usr/lib/ruby/vendor_ruby/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'
/usr/lib/ruby/vendor_ruby/active_record/query_cache.rb:9:in `cache'
/usr/lib/ruby/vendor_ruby/active_record/query_cache.rb:28:in `call'
/usr/lib/ruby/vendor_ruby/active_record/connection_adapters/abstract/connection_pool.rb:361:in `call'
/usr/lib/ruby/vendor_ruby/action_controller/string_coercion.rb:25:in `call'
/usr/lib/ruby/vendor_ruby/rack/head.rb:9:in `call'
/usr/lib/ruby/vendor_ruby/rack/methodoverride.rb:24:in `call'
/usr/lib/ruby/vendor_ruby/action_controller/params_parser.rb:15:in `call'
/usr/lib/ruby/vendor_ruby/action_controller/session/cookie_store.rb:99:in `call'
/usr/lib/ruby/vendor_ruby/action_controller/failsafe.rb:26:in `call'
/usr/lib/ruby/vendor_ruby/rack/lock.rb:15:in `call'
/usr/lib/ruby/vendor_ruby/action_controller/dispatcher.rb:106:in `call'
/usr/lib/ruby/vendor_ruby/rails/rack/static.rb:31:in `call'
/usr/lib/ruby/vendor_ruby/rack/urlmap.rb:52:in `call'
/usr/lib/ruby/vendor_ruby/rack/urlmap.rb:46:in `each'
/usr/lib/ruby/vendor_ruby/rack/urlmap.rb:46:in `call'
/usr/lib/ruby/vendor_ruby/rack/handler/webrick.rb:59:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
/usr/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:95:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `each'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:23:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:82:in `start'
/usr/lib/ruby/vendor_ruby/rack/handler/webrick.rb:13:in `run'
Rendering /usr/share/redmine/public/500.html (500 Internal Server Error)
我在redmine论坛上打开了与此问题相关的问题，但没有成功（link）