rake spec error: uninitialized constant Spec::Rails::Example::RailsExampleGroup

Hi all,

I am absolute radiant/ruby beginner trying to create custom extension
(following the tutorail - > http://wiki.github.com/radiant/radiant/adding-custom-radius-tags
)

Unfortunately afte calling "rake spec" a get he following error:

C:/Ruby/lib/ruby/gems/1.8/gems/radiant-0.7.1/vendor/rails/activerecord/
lib/../../activesupport/lib/active_support/depend
encies.rb:276:in `load_missing_constant': uninitialized constant
Spec::Rails::Example::RailsExampleGroup (NameError)

If someone have faced this before and have solutions please help.

10x in advance,
eng. Ilian Iliev