This tutorial was written by a Windows user. Assuming you are working on a linux / mac osx / unix system you need to change all occurances of "\" to "/" in path specifications.
"app\views\upload\uploadfile.rhtml"
becomes
"app/views/upload/uploadfile.rhtml"
Also, based on the "rhtml" extension I'ld say this tutorial is somewhat dated. Current practice would be:
"uploadfile.html.erb"
If you don't already know it, this is a good place to start:
enjoy