I have both qtruby and qt4-qtruby installed (via the gentoo ebuilds),
and am trying to run the examples from qt4-qtruby-1.4.7. However, most
of them are failing with "Unresolved constructor call". Here's a
minimal failure case:

irb(main):001:0> require 'Qt'
=> true
irb(main):002:0>  app = Qt::Application.new([])
=> #<Qt::Application:0xb6a24bec name="irb">
irb(main):003:0> button = Qt::PushButton.new("hello world")
ArgumentError: unresolved constructor call Qt::PushButton

        from /usr/lib/ruby/site_ruby/1.8/Qt/qtruby.rb:1367:in `initialize'
        from /usr/lib/ruby/site_ruby/1.8/Qt/qtruby.rb:1367:in `call'
        from /usr/lib/ruby/site_ruby/1.8/Qt/qtruby.rb:1367:in `try_initialize'
        from /usr/lib/ruby/site_ruby/1.8/Qt/qtruby.rb:1366:in `catch'
        from /usr/lib/ruby/site_ruby/1.8/Qt/qtruby.rb:1366:in `try_initialize'
        from (irb):3:in `new'
        from (irb):3

martin