Map drive through connected port

I have an HP pavillion 4473 with only one connection for peripheral. I already have an external ZIP connected. I want to also map a path for the printer through the same connection. I have tried doing the HELP directions, to receive message that denies me a connection. I am putting in c:\program files\EPSON\StylusRIP\StylusRIP_Utilities\PPDS\Epp12002.ppd-because that is where the driver is located. The computer assigned the letter D to the ZIP drive. What do I need to do? This computer is a stand alone Home unit. Please help!
Thanks in advance