I think you are out of luck with the parallel cable on Windows XP.
That version doesn't allow an hardware hook true pc2amiga with the parallelport like older Windows versions, so I guess pc2amiga won't work in this situation. That said, I don't know anything about pc2amiga and how it works :-? , but it is a rather old program..
If you want to use a terminal program you'll need to hook up a serial null modem cable, but it is VERY slow (maximum transferrate will be around 10kb/s IF your serial port on the Amiga & PC can handle the 115200 setting.)
You'd be better off getting a pcmcia network card for your Amiga and a cheap PCI network card for your pc and use FTP for filetransfer (obviously you need to setup an FTP server on your pc OR Amiga)