News section tutorial + mongodb

[eluser]Unknown[/eluser]
Hi everybody.
I'm new to codeIgniter, and i'm trying to create the news application defined in the tutorial but with alex bilbie's mongodb library. I followed all the spets specified, and I put the two mongodb library files in the right directories, but when I browse to http://newsapp/index.php/news I get a blank page and this error in the apache error.log file

Negotiation: discovered file(s) matching request: [path-to-the-webapp]/newsApp/news (None could be negotiated).