I am running Fedora 12 with Rails 2.3.4 installed.  Everything was working fine, then last night I got an update from yum for Rack 1.1.  After installing that, my working rails apps failed to load.  Creating a new test app yielded:
/usr/lib/ruby/site_ruby/1.8/rubygems.rb:827:in `report_activate_error': RubyGem version error: rack(1.1.0 not ~> 1.0.0) (Gem::LoadError)

Has anyone else hit this issue?  If more detail is needed, let me know.  Thanks,