Ahh, your friend needs to select the Ambit folder itself, rather than the 2kXP folder which is within. The files he's looking for are usbcm.inf, usbcm.cat and usbcm.sys.
Since he's tried installing once and it's failed, there might be bits hanging about, so with the USB cable unplugged, run the uninstall.exe program to remove any trace of the drivers, then reboot the PC. Plug the USB cable back in, and when you're going through the Found New Hardware wizard, use the automatic search option and tick Specify a Location. Click Browse, and find the Ambit folder - highlight it, and click OK - then finish the wizard.
Alternatively, buy him an Ethernet card
