Making a Distiller file from a Quark export to pdf

Using quark 6.5 I can make a pdf direct from the File>Export>Layout
as a PDF. However if I choose create PS file and then try any of the PDF presets in Distiller the same quark document has its coloured areas coming out solid black. I have checked the quark PS file via Photoshop and the colour areas are present in the file. Your thoughts please