i'm using a yaml file to save my preferences in a RubyCocoa
application, however i get :

/usr/lib/ruby/1.8/yaml.rb:347:in `allocate': allocator undefined for
Data (TypeError)
	from /usr/lib/ruby/1.8/yaml.rb:347:in `object_maker'
	from /usr/lib/ruby/1.8/yaml/rubytypes.rb:36
	from /usr/lib/ruby/1.8/yaml/rubytypes.rb:34:in `call'
	from /Users/yt/work/RubyCocoa/eSync/build/Release/eSync.app/Contents/
Resources/rb_main.rb:16:in `transfer'
	from /usr/lib/ruby/1.8/yaml.rb:119:in `load'
	from /usr/lib/ruby/1.8/yaml.rb:119:in `load'
	from /Users/yt/work/RubyCocoa/eSync/build/Release/eSync.app/Contents/
Resources/SyncDataSource.rb:55:in `initialize'


line 55 :
      o=YAML::load(File.open("#{PREFS_FILE}"))


THE file :

--- !ruby/object:Preferences
deepness: 2
root: !ruby/object:Folder
  "__slave_nsobj__": !ruby/object:Data {}
  enabled: -1
  items:
    - !ruby/object:Folder
      "__slave_nsobj__": !ruby/object:Data {}
      enabled: -1
      items:
        - !ruby/object:Folder
          "__slave_nsobj__": !ruby/object:Data {}
          enabled: true
          items: []
          name: Agenda
          path: /Users/yt/Documents/OOo/Agenda
[...]


i even don't know where the lines ""__slave_nsobj__": !ruby/
object:Data {}" are coming from...