rspec spec output

#this is my console after I commented out 'Capybara.server_boot_timeout = 50' in spec_helper.rb

george@ubuntu:~/workspace/openbay$ rspec spec
No DRb server is running. Running in local process instead ...

Finished in 0.21461 seconds
0 examples, 0 failures
/usr/lib/ruby/gems/1.9.1/gems/headless-1.0.1/lib/headless/cli_util.rb:9:in `ensure_application_exists!': Xvfb not found on your system (Headless::Exception)
	from /usr/lib/ruby/gems/1.9.1/gems/headless-1.0.1/lib/headless.rb:68:in `initialize'
	from /home/george/workspace/openbay/spec/spec_helper.rb:37:in `new'
	from /home/george/workspace/openbay/spec/spec_helper.rb:37:in `block (3 levels) in <top (required)>'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/hooks.rb:21:in `instance_eval'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/hooks.rb:21:in `run'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/hooks.rb:66:in `block in run'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/hooks.rb:66:in `each'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/hooks.rb:66:in `run'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/hooks.rb:418:in `run_hook'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/command_line.rb:27:in `block in run'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/reporter.rb:34:in `report'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/command_line.rb:25:in `run'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/runner.rb:77:in `rescue in run'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/runner.rb:73:in `run'
	from /usr/lib/ruby/gems/1.9.1/gems/rspec-core-2.13.1/lib/rspec/core/runner.rb:17:in `block in autorun'