heroku - Installing heroku (win8)

Question

i'm new to heroku.

I have downloaded and installed the heroku toolbelt (win8).

When i try to write "heroku" or "heroku + -anything-" in cmd or git bash i get this message:

C:/Program Files (x86)/Heroku/lib/heroku/updater.rb:164:in `spawn': No such file or directory - open (Errno::ENOENT)
    from C:/Program Files (x86)/Heroku/lib/heroku/updater.rb:164:in `background_update!'
    from C:/Program Files (x86)/Heroku/lib/heroku/updater.rb:144:in `inject_libpath'
    from C:/Program Files (x86)/Heroku/bin/heroku:24:in `<main>'