undefined method 'exitstatus' for nil nilclass on rake db:structure:dump
===

When I try to do a rake db:structure:dump in rails, for the first time. I needed to switch to the sql fromat. I get this: (PostgreSQL database)

    C:\Sites\care>rake db:structure:dump --trace
    Creating scope :search. Overwriting existing method PgSearch::Document.search.
    ** Invoke db:structure:dump (first_time)
    ** Invoke environment (first_time)
    ** Execute environment
    ** Execute db:structure:dump
    C:/RailsInstaller/Ruby1.9.3/bin/rake: No such file or directory - pg_dump -i -s -x -O -f C:/Sites/care/db/structure.sql  care_development
    rake aborted!
    undefined method `exitstatus' for nil:NilClass
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-3.2.1/lib/active_record/railties/databases.rake:390:in `block (3 levels) in <top (required)>'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
    C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
    C:/RailsInstaller/Ruby1.9.3/bin/rake:19:in `load'
    C:/RailsInstaller/Ruby1.9.3/bin/rake:19:in `<main>'
    Tasks: TOP => db:structure:dump

Any idea on what might be the problem?