Forum: Ruby Error - ActiveRecord is not missing constant Serialization!

Hello,

I was using Ruby 1.8.7 and Rails 3.0.3 in my app on Heroku till I got a
message from them to upgrade to solve a security issue. I upgraded to
3.0.19 without any issue. But then I decided to upgrade further to Ruby
1.9.3 and Rails 3.2.11. As this change required a lot of code changes, I
decided to revert back to Ruby 1.8.7 and Rails 3.0.19. I have removed
both Ribu 1.9.3 and rails 3.2.11 from my setup but now when I try to
start server on my local setup I am not able to get server up and
running. I am getting this error :

ActiveRecord is not missing constant Serialization!

and following is the framework trace :

activesupport (3.0.19) lib/active_support/dependencies.rb:483:in
`load_missing_constant'
activesupport (3.0.19) lib/active_support/dependencies.rb:183:in
`const_missing'
activesupport (3.0.19) lib/active_support/dependencies.rb:181:in `each'
activesupport (3.0.19) lib/active_support/dependencies.rb:181:in
`const_missing'
activesupport (3.0.19) lib/active_support/inflector/methods.rb:113:in
`constantize'
activesupport (3.0.19) lib/active_support/inflector/methods.rb:112:in
`each'
activesupport (3.0.19) lib/active_support/inflector/methods.rb:112:in
`constantize'
activesupport (3.0.19)
lib/active_support/core_ext/string/inflections.rb:43:in `constantize'
actionpack (3.0.19)
lib/action_dispatch/middleware/session/abstract_store.rb:228:in
`stale_session_check!'
actionpack (3.0.19)
lib/action_dispatch/middleware/session/abstract_store.rb:193:in
`load_session'
actionpack (3.0.19)
lib/action_dispatch/middleware/session/abstract_store.rb:121:in `send'
actionpack (3.0.19)
lib/action_dispatch/middleware/session/abstract_store.rb:121:in `load!'
actionpack (3.0.19)
lib/action_dispatch/middleware/session/abstract_store.rb:113:in
`load_for_read!'
actionpack (3.0.19)
lib/action_dispatch/middleware/session/abstract_store.rb:53:in `[]'
actionpack (3.0.19) lib/action_dispatch/middleware/flash.rb:178:in
`call'
actionpack (3.0.19)
lib/action_dispatch/middleware/session/abstract_store.rb:149:in `call'
actionpack (3.0.19) lib/action_dispatch/middleware/cookies.rb:302:in
`call'
activerecord (3.0.19) lib/active_record/query_cache.rb:32:in `call'
activerecord (3.0.19)
lib/active_record/connection_adapters/abstract/query_cache.rb:28:in
`cache'
activerecord (3.0.19) lib/active_record/query_cache.rb:12:in `cache'
activerecord (3.0.19) lib/active_record/query_cache.rb:31:in `call'
activerecord (3.0.19)
lib/active_record/connection_adapters/abstract/connection_pool.rb:354:in
`call'
actionpack (3.0.19) lib/action_dispatch/middleware/callbacks.rb:46:in
`call'
activesupport (3.0.19) lib/active_support/callbacks.rb:416:in
`_run_call_callbacks'
actionpack (3.0.19) lib/action_dispatch/middleware/callbacks.rb:44:in
`call'
rack (1.2.7) lib/rack/sendfile.rb:106:in `call'
actionpack (3.0.19) lib/action_dispatch/middleware/remote_ip.rb:48:in
`call'
actionpack (3.0.19)
lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
railties (3.0.19) lib/rails/rack/logger.rb:13:in `call'
rack (1.2.7) lib/rack/runtime.rb:17:in `call'
activesupport (3.0.19)
lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.2.7) lib/rack/lock.rb:13:in `call'
rack (1.2.7) lib/rack/lock.rb:13:in `synchronize'
rack (1.2.7) lib/rack/lock.rb:13:in `call'
actionpack (3.0.19) lib/action_dispatch/middleware/static.rb:30:in
`call'
railties (3.0.19) lib/rails/application.rb:168:in `call'
railties (3.0.19) lib/rails/application.rb:77:in `send'
railties (3.0.19) lib/rails/application.rb:77:in `method_missing'
railties (3.0.19) lib/rails/rack/log_tailer.rb:14:in `call'
rack (1.2.7) lib/rack/content_length.rb:13:in `call'
rack (1.2.7) lib/rack/handler/webrick.rb:52:in `service'
C:/Users/rm/.pik/rubies/Ruby-187-p358/lib/ruby/1.8/webrick/httpserver.rb:104:in
`service'
C:/Users/rm/.pik/rubies/Ruby-187-p358/lib/ruby/1.8/webrick/httpserver.rb:65:in
`run'
C:/Users/rm/.pik/rubies/Ruby-187-p358/lib/ruby/1.8/webrick/server.rb:173:in
`start_thread'
C:/Users/rm/.pik/rubies/Ruby-187-p358/lib/ruby/1.8/webrick/server.rb:162:in
`start'
C:/Users/rm/.pik/rubies/Ruby-187-p358/lib/ruby/1.8/webrick/server.rb:162:in
`start_thread'
C:/Users/rm/.pik/rubies/Ruby-187-p358/lib/ruby/1.8/webrick/server.rb:95:in
`start'
C:/Users/rm/.pik/rubies/Ruby-187-p358/lib/ruby/1.8/webrick/server.rb:92:in
`each'
C:/Users/rm/.pik/rubies/Ruby-187-p358/lib/ruby/1.8/webrick/server.rb:92:in
`start'
C:/Users/rm/.pik/rubies/Ruby-187-p358/lib/ruby/1.8/webrick/server.rb:23:in
`start'
C:/Users/rm/.pik/rubies/Ruby-187-p358/lib/ruby/1.8/webrick/server.rb:82:in
`start'
rack (1.2.7) lib/rack/handler/webrick.rb:13:in `run'
rack (1.2.7) lib/rack/server.rb:217:in `start'
railties (3.0.19) lib/rails/commands/server.rb:65:in `start'
railties (3.0.19) lib/rails/commands.rb:30
railties (3.0.19) lib/rails/commands.rb:27:in `tap'
railties (3.0.19) lib/rails/commands.rb:27
script/rails:6:in `require'
script/rails:6


I don't what I did wrong or what am I missing. Should I remove whole
rails framework and start from scratch? If yes, then how should I do
that?
Any help is greatly appreciated.

Thanks.