running bpm preview

[pierreva]

/Users/pierreva/.rvm/gems/ruby-1.9.2-p180/gems/bpm-1.0.0/lib/bpm/server.rb:7:in <module:BPM>': uninitialized constant Rack::Server (NameError) from /Users/pierreva/.rvm/gems/ruby-1.9.2-p180/gems/bpm-1.0.0/lib/bpm/server.rb:5:in<top (required)>' from /Users/pierreva/.rvm/gems/ruby-1.9.2-p180/gems/bpm-1.0.0/lib/bpm/cli/base.rb:218:in preview' from /Users/pierreva/.rvm/gems/ruby-1.9.2-p180/gems/thor-0.14.6/lib/thor/task.rb:22:inrun' from /Users/pierreva/.rvm/gems/ruby-1.9.2-p180/gems/thor-0.14.6/lib/thor/invocation.rb:118:in invoke_task' from /Users/pierreva/.rvm/gems/ruby-1.9.2-p180/gems/thor-0.14.6/lib/thor.rb:263:indispatch' from /Users/pierreva/.rvm/gems/ruby-1.9.2-p180/gems/thor-0.14.6/lib/thor/base.rb:389:in start' from /Users/pierreva/.rvm/gems/ruby-1.9.2-p180/gems/bpm-1.0.0/lib/bpm/cli/base.rb:59:instart' from /Users/pierreva/.rvm/gems/ruby-1.9.2-p180/gems/bpm-1.0.0/bin/bpm:8:in <top (required)>' from /Users/pierreva/.rvm/gems/ruby-1.9.2-p180/bin/bpm:19:inload' from /Users/pierreva/.rvm/gems/ruby-1.9.2-p180/bin/bpm:19:in `

'

[wagenet]

Try gem install rack.

[pierreva]

with ruby-1.9.3-p194 it's OK