undefined method translate during Rails 2.3 -> 3.2 upgrade

Working on upgrading a Rails 2.3.17 app to Rails 3.2.22.2 (running ruby 1.9.3-p551). Was able to get through the painful portion of ugprading all the gems / updating the directory structure / adding in all new/updated rails files.

The rails server is now coming up, but when i try to load up the first page, it fails with this stack trace:

NoMethodError: undefined method `translate' for #   <I18n::Backend::ActiveRecord:0x007ff64dc72400>
/myapp/vendor/bundle/ruby/1.9.1/gems/i18n-0.7.0/lib/i18n/backend/chain.rb:46:in `block (2 levels) in translate'
/myapp/vendor/bundle/ruby/1.9.1/gems/i18n-0.7.0/lib/i18n/backend/chain.rb:44:in `catch'
/myapp/vendor/bundle/ruby/1.9.1/gems/i18n-0.7.0/lib/i18n/backend/chain.rb:44:in `block in translate'
/myapp/vendor/bundle/ruby/1.9.1/gems/i18n-0.7.0/lib/i18n/backend/chain.rb:43:in `each'

...

Additional notes: I have an locale.rb file in the config/initializers/ folder, which has this:

require "i18n/backend/cache"

I18n::Backend::ActiveRecord.send(:include, I18n::Backend::Memoize)
I18n::Backend::ActiveRecord.send(:include, I18n::Backend::Flatten)
I18n::Backend::Simple.send(:include, I18n::Backend::Memoize)
I18n::Backend::Simple.send(:include, I18n::Backend::Pluralization)
I18n::Backend::Chain.send(:include, I18n::Backend::Cache)
I18n.backend = I18n::Backend::ActiveRecord.new
I18n.backend = I18n::Backend::Chain.new(I18n::Backend::Simple.new, I18n.backend)

any ideas why it might be generating that error message ?