Little things that bother me

I really have never been able to get this to work...

$ rake doc:rails --trace
(in /home/storage/users/craig/svn/th-db/branches/phase5)
** Invoke doc:rails (first_time)
** Invoke doc/api/index.html (first_time)
** Invoke README (first_time, not_needed)
rake aborted!
Don't know how to build task 'vendor/rails/railties/CHANGELOG'
/usr/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1634:in `[]'

and then some more lines tracing the error

Is it possible to block these errors or allow the rake task to build in
spite of them?

All I've ever been able to do is 'rake doc:plugins' (which I couldn't do
until I got rid of 'engines')