Iphone connectivity Help

My IPhone 3G doesn't connect to Itunes. I have the most recent version of Itunes on Windows Vista. My Phone only registers on my computer as a camera. So I follow the troubleshooting steps on this page (http://support.apple.com/kb/TS1538) and I realize that my issue is that my Apple Mobile Device Driver does not appear in device managers. I follow all of the steps to install it, but when I try and install the "usbaapl.inf" from the folder " C:\Program Files\Common Files\Apple\Mobile Device Support\Drivers." I get a message saying:

"The folder you specificied doesn't contain a compatible software driver for your device. If the folder contains a driver, make sure it is designed to work with Windows for 32 bit systems"

Where do I proceed from here?

Thank you