needs to have method `_load'

I'm getting an exception that I'm fairless clueless about. It occurs
when I run a "create" action but neither my action or before filters
are hit before this exception. I'm hoping someone can give me a clue.
I suspect it has to do with marshalling objects in the session - maybe
TzTime is not capable of being stored in the session. I hope that's
not the case. The exception is:

/!\ FAILSAFE /!\ Dec 29, 2007 02:05PM
  Status: 500 Internal Server Error
  class TzTime needs to have method `_load'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/session/active_record_store.rb:84:in `load'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/session/active_record_store.rb:84:in `unmarshal'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/session/active_record_store.rb:122:in `data'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/session/active_record_store.rb:303:in `restore'
    /usr/lib/ruby/1.8/cgi/session.rb:304:in `[]'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/cgi_process.rb:134:in `session'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/cgi_process.rb:162:in `stale_session_check!'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/cgi_process.rb:114:in `session'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/base.rb:1110:in `assign_shortcuts_without_flash'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/flash.rb:167:in `assign_shortcuts'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/base.rb:507:in `process_without_filters'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/filters.rb:685:in
`process_without_session_management_support'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/session_management.rb:123:in `process'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/base.rb:377:in `process'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/dispatcher.rb:171:in `handle_request'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/dispatcher.rb:115:in `dispatch'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/dispatcher.rb:126:in `dispatch_cgi'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/actionpack/lib/
action_controller/dispatcher.rb:9:in `dispatch'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/bin/../lib/mongrel/
rails.rb:76:in `process'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/bin/../lib/mongrel/
rails.rb:74:in `synchronize'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/bin/../lib/mongrel/
rails.rb:74:in `process'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel.rb:155:in
`process_client'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel.rb:154:in
`each'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel.rb:154:in
`process_client'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel.rb:281:in
`run'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel.rb:281:in
`initialize'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel.rb:281:in
`new'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel.rb:281:in
`run'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel.rb:264:in
`initialize'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel.rb:264:in
`new'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel.rb:264:in
`run'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel/
configurator.rb:282:in `run'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel/
configurator.rb:281:in `each'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel/
configurator.rb:281:in `run'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/bin/mongrel_rails:128:in
`run'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/lib/mongrel/command.rb:
212:in `run'
    /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.1/bin/mongrel_rails:281
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/activesupport/
lib/active_support/dependencies.rb:489:in `load'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/activesupport/
lib/active_support/dependencies.rb:489:in `load'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/activesupport/
lib/active_support/dependencies.rb:342:in `new_constants_in'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/activesupport/
lib/active_support/dependencies.rb:489:in `load'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/railties/lib/
commands/servers/mongrel.rb:64
    /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in
`gem_original_require'
    /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in
`require'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/activesupport/
lib/active_support/dependencies.rb:496:in `require'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/activesupport/
lib/active_support/dependencies.rb:342:in `new_constants_in'
   /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/activesupport/
lib/active_support/dependencies.rb:496:in `require'
    /home/dsailer/aptana/workspace/OrbRuby/vendor/rails/railties/lib/
commands/server.rb:39
    /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in
`gem_original_require'
    /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in
`require'
    ./script/server:3
    /usr/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.1.9/lib/ruby-debug.rb:
79:in `debug_load'
    /usr/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.1.9/lib/ruby-debug.rb:
79:in `main'
    /usr/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.1.9/bin/rdebug-ide:74
    /usr/bin/rdebug-ide:16:in `load'
    /usr/bin/rdebug-ide:16
    -e:4:in `load'
    -e:4

I've been thinking about changing my logic to no longer marshal any
objects into the session anyway, so here's another good reason to do
it.

This could be a missing gem problem. Check if the gem that uses that class is installed on your system or not.