Как устранить ошибку десериализации в отложенном задании?

Я пытаюсь использовать DelayedJob, но задание не выполняется, что приводит к следующей ошибке в базе данных:

{Delayed::DeserializationError
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/serialization/active_record.rb:7:in `yaml_new'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/yaml.rb:133:in `transfer'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/yaml.rb:133:in `node_import'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/yaml.rb:133:in `load'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/yaml.rb:133:in `load'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/backend/base.rb:79:in `payload_object'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/backend/base.rb:87:in `invoke_job_without_newrelic_transaction_trace'
(eval):3:in `invoke_job'
/Library/Ruby/Gems/1.8/gems/newrelic_rpm-2.13.4/lib/new_relic/agent/instrumentation/controller_instrumentation.rb:252:in `perform_action_with_newrelic_trace'
/Library/Ruby/Gems/1.8/gems/newrelic_rpm-2.13.4/lib/new_relic/agent/method_tracer.rb:141:in `trace_execution_scoped'
/Library/Ruby/Gems/1.8/gems/newrelic_rpm-2.13.4/lib/new_relic/agent/instrumentation/controller_instrumentation.rb:247:in `perform_action_with_newrelic_trace'
(eval):2:in `invoke_job'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:120:in `run'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/timeout.rb:62:in `timeout'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:120:in `run'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/benchmark.rb:308:in `realtime'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:119:in `run'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:177:in `reserve_and_run_one_job'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:104:in `work_off'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:103:in `times'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:103:in `work_off'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:78:in `start'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/benchmark.rb:308:in `realtime'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:77:in `start'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:74:in `loop'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/worker.rb:74:in `start'
/Library/Ruby/Gems/1.8/gems/delayed_job-2.1.3/lib/delayed/tasks.rb:9
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/bin/rake:31
/usr/bin/rake:19:in `load'
/usr/bin/rake:19

Не уверен, с чего начать диагностику этого. Этого никогда не случалось раньше, и раньше я использовал отложенное задание, чтобы сериализовать объекты модели без каких-либо проблем. Почему в этот раз?

Заранее спасибо!