this color management forum is dedicated to Adobe programs.
But I'm sure, the friendly people here (Adobe InDesign) will help you,
even concerning Quark questions.
Best regards --Gernot Hoffmann
Here's how I do it. Each page has to be Exported as an EPS in QuarkXPress. Because Quark incorporated so many web features into it XPress application, it could be printing PDFs as RGB files as a default op. Once you have all of the EPS files exported, use Distiller to create the individual PDF files. Once you have all of the individual page files Distilled, use Acrobat to assemble a multi-page document PDF ( optional, depends on the print vendor's requirements ). Gernot, you sure about that?
Your setup is ancient but if you use Distiller it should work. PDFWriter was removed after that release and was always a disaster for XPresss, never use it. You just get an RGB rasterised image of each page with no fonts.
Have you checked your settings in Preferences?
PDF check "Directly to PDF" rather than the other choice "Save ps for distilling later , or whatever it is, can't remember the exact wording for that other choice.
When you then select Export to PDF you should have an options button, another window will come up with several tabs.
In one of the tabs you can select Composite and CMYK.
This will create a CMYK PDF.
I believe at one time Quark used something called Jaws to create PDFs.
In 6.5 the presets are limited and don't have any of the PDF/x settings.
Thank God I was able to avoid using Quark (a program stuck in a 1980's time warp) very much.