javascript files loaded twice...

I am testing my app w Rails 2.0.2, and the loading log shows that the prototype .js files loaded twice

http://0.0.0.0:3000/ ..... images files loaded http://0.0.0.0:3000/javascripts/application.js?1197932385 http://0.0.0.0:3000/javascripts/builder.js http://0.0.0.0:3000/javascripts/builder.js?1197932385 http://0.0.0.0:3000/javascripts/controls.js http://0.0.0.0:3000/javascripts/controls.js?1197932385 http://0.0.0.0:3000/javascripts/dragdrop.js http://0.0.0.0:3000/javascripts/dragdrop.js?1197932385 http://0.0.0.0:3000/javascripts/effects.js http://0.0.0.0:3000/javascripts/effects.js?1197932385 http://0.0.0.0:3000/javascripts/slider.js http://0.0.0.0:3000/javascripts/slider.js?1197932385

in my layout I am using only : <%= javascript_include_tag :all, :cache => true %>

what could be the source of that particularity... thanks for your suggestions erwin