Undefined method and bad serialization with delayed job on lion

I am getting some odd behavior on a newly set up mac with os x lion. Our app runs fine in the development environment locally but in the test environment delayed job is not serializing correctly. On my other machine (snow leopard) everything works fine from the same branch & commit. Below you will see the job and error.

Any ideas on what would cause this?

BTW, I have no setup_load_paths.rb file. The solution on a similar question won't work.

#<Delayed::Backend::ActiveRecord::Job:0x007fe3771343b0> {
            :id => 1,
      :priority => 0,
      :attempts => 0,
       :handler => "--- !ruby/struct:Delayed::PerformableMethod \nobject: !ruby/object:Class User\nmethod_name: :update_listed_package_states_for\nargs: \n- 2\n",
    :last_error => nil,
        :run_at => Tue, 02 Aug 2011 13:24:06 UTC +00:00,
     :locked_at => Tue, 02 Aug 2011 13:24:20 UTC +00:00,
     :failed_at => n开发者_StackOverflow社区il,
     :locked_by => "host:typhoon.local pid:84593",
    :created_at => Tue, 02 Aug 2011 13:24:06 UTC +00:00,
    :updated_at => Tue, 02 Aug 2011 13:24:06 UTC +00:00
}
#<NoMethodError: undefined method `update_listed_package_states_for' for #<Class:0x007fe3771118d8>>

What ended up fixing this for me was bumping up my gems and then resorting to bundle exec... to run cucumber & rspec. Never really got to the bottom of the cause but this leads me to believe it was a stray gem being loaded that was causing the trouble.