i need help to convert a QuarkXPress file into .pdf format.

When i use the: FILE > EXPORT > FILE AS PDF i get the following message box:
'To save a layout as a PDF file a postscript printer must be set up to print a file'

Can anyone help with this? I have heard something about 'virtual postscript printers' would this work and how do i do it?

All help would be gratefully recieved!

(alternatively does anyone have the ability to do this that i could mail the files to?)

I am using QuarkXpress 6.0 Passport version on Windows XP OS