external htm -> record not found

i want to execute php in a iframe-window for uploading files without
sending the whole form.
<div id='fileauswahl' style='z-index:5;'><IFRAME name='initial'
src='uploader.htm' width='500' height='300'></div>
i placed the "uploader.htm" in the public folder, but i get the error:

"Active Record:: Recordnotfound
in AuftragsController#show
Couldn't find Auftrag with ID=uploader

Is this the wrong place or do i have to specify a different path?

i changed uploader.htm to ../uploader.htm now the uploadform is show.
But as the saveing action i use a php-program.
When i hit upload the following error is displayed:

Routing Error

No route matches "/upload_ek.php" with {:method=>:post}