Problem generate migration

Hello, I have Ruby installed in my Windows 7, but when I try to generate
a new migration, this error appears:

C:\rails\organily>rails g migration Task
      invoke active_record
C:/Ruby193/lib/ruby/1.9.1/psych.rb:203:in `parse': (<unknown>): mapping
values a
re not allowed in this context at line 8 column 13 (Psych::SyntaxError)
        from C:/Ruby193/lib/ruby/1.9.1/psych.rb:203:in `parse_stream'
        from C:/Ruby193/lib/ruby/1.9.1/psych.rb:151:in `parse'
        from C:/Ruby193/lib/ruby/1.9.1/psych.rb:127:in `load'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.3/lib/rails/applic
ation/configuration.rb:115:in `database_configuration'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activerecord-3.2.3/lib/active_r
ecord/railtie.rb:75:in `block (2 levels) in <class:Railtie>'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.3/lib/active_
support/lazy_load_hooks.rb:36:in `instance_eval'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.3/lib/active_
support/lazy_load_hooks.rb:36:in `execute_hook'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.3/lib/active_
support/lazy_load_hooks.rb:43:in `block in run_load_hooks'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.3/lib/active_
support/lazy_load_hooks.rb:42:in `each'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.3/lib/active_
support/lazy_load_hooks.rb:42:in `run_load_hooks'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activerecord-3.2.3/lib/active_r
ecord/base.rb:721:in `<top (required)>'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activerecord-3.2.3/lib/active_r
ecord/migration.rb:507:in `next_migration_number'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activerecord-3.2.3/lib/active_r
ecord/migration.rb:334:in `method_missing'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activerecord-3.2.3/lib/rails/ge
nerators/active_record.rb:21:in `next_migration_number'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.3/lib/rails/genera
tors/migration.rb:49:in `migration_template'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activerecord-3.2.3/lib/rails/ge
nerators/active_record/migration/migration_generator.rb:10:in
`create_migration_
file'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/task.rb:22
:in `run'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:118:in `invoke_task'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:124:in `block in invoke_all'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:124:in `each'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:124:in `map'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:124:in `invoke_all'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/group.rb:2
26:in `dispatch'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:109:in `invoke'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/group.rb:2
69:in `block in _invoke_for_class_method'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/shell.rb:7
4:in `with_padding'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/group.rb:2
58:in `_invoke_for_class_method'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/group.rb:1
50:in `_invoke_from_option_orm'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/task.rb:22
:in `run'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:118:in `invoke_task'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:124:in `block in invoke_all'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:124:in `each'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:124:in `map'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/invocation
.rb:124:in `invoke_all'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/group.rb:2
26:in `dispatch'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.14.6/lib/thor/base.rb:38
9:in `start'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.3/lib/rails/genera
tors.rb:170:in `invoke'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.3/lib/rails/comman
ds/generate.rb:12:in `<top (required)>'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.3/lib/active_
support/dependencies.rb:251:in `require'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.3/lib/active_
support/dependencies.rb:251:in `block in require'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.3/lib/active_
support/dependencies.rb:236:in `load_dependency'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.3/lib/active_
support/dependencies.rb:251:in `require'
        from
C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.3/lib/rails/comman
ds.rb:29:in `<top (required)>'
        from script/rails:6:in `require'
        from script/rails:6:in `<main>'

I don't know what that means, don't know if is missing something.

Thank you all.