This zipfile contains .inf & other files for "RC144AxF" modem (Rockwell chipset) for HP computers (mileage with other brands may vary). It contains the filexfer.dll & other necessary files.
Unzip this file into your temp directory (or whereever you prefer). Go to "Control Panel", "Add New Hardware"...When the installer asks for the location of the drivers, give it whichever directory you unzipped to. That *should* do it.