Undefined method `subclasses' error

hi, I moved up from rails 1.1.6 to 1.2.3 and now i get this error:

Processing ApplicationController#login (for 74.193.67.252 at 2007-03-22
18:04:47) [GET]
Session ID: 3cf7c4e3edc74e0912bf74c9e309750a
Parameters: {“action”=>“login”, “controller”=>“account”}

NoMethodError (undefined method subclasses' for #<Set: {User, Coach}>): /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/core_ext/symbol.rb:10:insend
/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/core_ext/symbol.rb:10:in
to_proc' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/inflector.rb:250:inmap’
/usr/lib/ruby/1.8/set.rb:189:in each' /usr/lib/ruby/1.8/set.rb:189:ineach_key’
/usr/lib/ruby/1.8/set.rb:189:in each' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/core_ext/enumerable.rb:42:inmap’
/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/core_ext/enumerable.rb:42:in
sum' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/observer.rb:170:inobserved_subclasses’
/usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/observer.rb:149:in
initialize' /usr/lib/ruby/1.8/singleton.rb:95:innew’
/usr/lib/ruby/1.8/singleton.rb:95:in `instance’
/usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/deprecated_dependen

Any ideas? Thanks.

I also moved up from 1.2.2 to 1.2.3, however when I start the server (or
even script/about) I have this error:

/opt/local/lib/ruby/gems/1.8/gems/activesupport-1.4.2.6552/lib/active_support/core_ext/module/aliasing.rb:31:in
alias_method’: undefined methodload_plugin’ for class
`Rails::Initializer’ (NameError)

Rails 1.2.2 with ActiveSupport 1.4.1 works fine, but when I want to have
ActiveResource, I need at least 1.2.3 and 1.4.2 that don’t start in
proper way.