through this error, any one have an idea

Exception IOError -> closed stream
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/buffered_logger.rb:104:in `write'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/buffered_logger.rb:104:in `block in flush'
   /<internal:prelude>:8:in `synchronize'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/buffered_logger.rb:101:in `flush'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/buffered_logger.rb:121:in `auto_flush'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/buffered_logger.rb:66:in `add'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/buffered_logger.rb:77:in `debug'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongo-1.0.1/lib/mongo/connection.rb:396:in `receive_message'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongo-1.0.1/lib/mongo/cursor.rb:345:in `send_initial_query'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongo-1.0.1/lib/mongo/cursor.rb:322:in `refill_via_get_more'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongo-1.0.1/lib/mongo/cursor.rb:317:in `num_remaining'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongo-1.0.1/lib/mongo/cursor.rb:65:in `next_document'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongo-1.0.1/lib/mongo/collection.rb:196:in `find_one'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongoid-2.0.0.beta6/lib/mongoid/collections/master.rb:15:in `block (2 levels) in <class:Master>'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongoid-2.0.0.beta6/lib/mongoid/collection.rb:69:in `find_one'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongoid-2.0.0.beta6/lib/mongoid/contexts/mongo.rb:222:in `one'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongoid-2.0.0.beta6/lib/mongoid/contexts/ids.rb:17:in `id_criteria'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongoid-2.0.0.beta6/lib/mongoid/criteria.rb:31:in `id_criteria'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongoid-2.0.0.beta6/lib/mongoid/criteria.rb:177:in `translate'
   /Users/waheed/.bundle/ruby/1.9.1/gems/mongoid-2.0.0.beta6/lib/mongoid/finders.rb:58:in `find'
   /Users/waheed/projects/dakwak/script/stalker.rb:23:in `block in <top (required)>'
   /Users/waheed/.bundle/ruby/1.9.1/gems/stalker-0.2.4/lib/stalker.rb:48:in `call'
   /Users/waheed/.bundle/ruby/1.9.1/gems/stalker-0.2.4/lib/stalker.rb:48:in `work_one_job'
   /Users/waheed/.bundle/ruby/1.9.1/gems/stalker-0.2.4/lib/stalker.rb:36:in `block in work'
   /Users/waheed/.bundle/ruby/1.9.1/gems/stalker-0.2.4/lib/stalker.rb:35:in `loop'
   /Users/waheed/.bundle/ruby/1.9.1/gems/stalker-0.2.4/lib/stalker.rb:35:in `work'
   /Users/waheed/projects/dakwak/script/stalker.rb:72:in `<top (required)>'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/dependencies.rb:205:in `load'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/dependencies.rb:205:in `block in load'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/dependencies.rb:195:in `block in load_dependency'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/dependencies.rb:523:in `new_constants_in'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/dependencies.rb:195:in `load_dependency'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/activesupport-3.0.0.beta3/lib/active_support/dependencies.rb:205:in `load'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/daemons-1.0.10/lib/daemons/application.rb:176:in `start_load'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/daemons-1.0.10/lib/daemons/application.rb:257:in `start'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/daemons-1.0.10/lib/daemons/controller.rb:72:in `run'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/daemons-1.0.10/lib/daemons.rb:139:in `block in run'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/daemons-1.0.10/lib/daemons/cmdline.rb:105:in `call'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/daemons-1.0.10/lib/daemons/cmdline.rb:105:in `catch_exceptions'
   /opt/local/lib/ruby1.9/gems/1.9.1/gems/daemons-1.0.10/lib/daemons.rb:138:in `run'
   /script/task_stalker.rb:12:in `<main>'