activesupport can not be loaded

Hi all,

Today I have checked out the latest version of Rails 3 and when I run
it, I encounter this error:

vendor/rails/railties/lib/rails/application.rb:76:in `rescue in block
in <class:Application>': no such file to load -- activesupport
(RuntimeError)

Is there any magic that I need to do? Because from what I understand
that activesupport is already bundled with Rails, so it should be
loaded right? Am I missing something here?

Regards,

Sorry this was my bad. I should've updated the config/application and
config/environment