Can't install MTP Device Driver in Vista

Hi

I have an Mp3 player which is an MTP Device. i would like to connect this to the computer and therefore would like to add the MTP Device from the device manager.

First, I go to Control Panel - Add Hardware and under Portable Devices, pick MTP Device under MTP-compliaint device.

IT comes back with the error "This device is not working properly because Windows cannot load the drivers required for this device (Code 31)"

Now I go to device manager, find the device and update the driver from the Internet, and it saids that it is the most current version, even though it can't actually find the driver???

What is going on? How do I install the MTP Device driver in Vista?