WordPress installed; Cannot open articles "No input file specified."

Hi there.
I changed the url of my wordpress blog, exporting the xml file from my older wordpress bog and importing it in the new one. But now i have a problem. The home page is working, but when i try to open an article i get the message “No input file specified.” Who can help me.
This is the site http://www.rag-inc.net.
Thank You!