Hi Nandaja,
rspec-rails 2.10.1 is packaged and new (it available in boutil's repo
- http://people.debian.org/~boutil/diaspora/README).
Option 1: You may try an older version of cucumber-rails compatible
with the rspec and rspec-rails versions in unstable.
Option 2: Jeremy has uploaded newer version of rspec in experimental
and I will try to update rspec-rails as well. You may directly target
experimental too once I'm able to upload a newer rspec-rails package
there.