[Nitro] require 'breakpoint' takes me into actionpack !

[itsme213]

I put this in my nitro code:

require 'breakpoint'; breakpoint

And it does this ...

Any idea what is going on? Looks like gem is very confused. I have used 
breakpoint frequently before without any problem.

Thanks.

C:\>ruby run.rb
 INFO:
 INFO:
 INFO:
 INFO:
 INFO:
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.9.1/lib/action_view/vendor/builder/blankslate.rb:11: 
Bui
lder is not a module (TypeError)
        from c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require__'
        from c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require'
        from 
c:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.1.1/lib/active_support/dependencies.rb:2
00:in `require'
        from 
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.9.1/lib/action_view/vendor/builder/xmlbase.
rb:3
        from c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require__'
        from c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require'
        from 
c:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.1.1/lib/active_support/dependencies.rb:2
00:in `require'
        from 
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-1.9.1/lib/action_view/vendor/builder/xmlmarku
p.rb:14
         ... 23 levels...
        from ./src/dental/types_and_instances.rb:8
        from c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require__'
        from c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require'
        from run.rb:18