"uninitialized constant Engines" - rake docs:plugins problem

hey. I recently reinstalled ubuntu (and therefore ruby, rails and all
my gems etc). For the first time since i reinstalled i tried to
generate some rdocs and got this error:

max@max-laptop:~/work/e_learning_resource/trunk$ rake doc:plugins
–trace
(in /home/max/work/e_learning_resource/trunk)
** Invoke doc:plugins (first_time)
** Invoke doc:plugins:savage_beast (first_time)
** Execute doc:plugins:savage_beast
rake aborted!
uninitialized constant Engines
/var/lib/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:445:in
load_missing_constant' /var/lib/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:77:inconst_missing’
/var/lib/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:89:in
const_missing' /home/max/work/e_learning_resource/trunk/vendor/plugins/savage_beast/tested_plugins/engines/tasks/engines.rake:72 /usr/lib/ruby/1.8/rake.rb:617:incall’
/usr/lib/ruby/1.8/rake.rb:617:in execute' /usr/lib/ruby/1.8/rake.rb:612:ineach’

It looks like it’s balking on the savage_beast plugin, which uses
Engines, but the plugin itself seems to work fine within my app. Any
advice anyone?

thanks, max