Today I spent quite some time making autospec and spec_server work flawlessly as David Chelimsky described.

Managed to do that only for the following combination of rails/gems/plugins

1. Removed all rails, rspec, rspec-rails gems.
2. Installed rails 2.3.2.
3. Bootstrapped new application.
4. Installed rspec, rspec-rails v.1.2.6 as plugins.
5. Run server with rake spec:server:start
6. script/autospec

Hope it helps someone.