This isn't about installing CUPS. CUPS-PDF is a sort of printer driver that allows you to print to PDF (i.e., create a PDF) simply by using CUPS-PDF as your printer choice. I had CUPS-PDF installed in VL 5.9 Standard but I haven't bothered yet in VL 6.
What I do now is print to a PostScript driver and choose Print to File. Then I do
ps2pdf nameoffile.ps nameoffile.pdf
This has worked fine so far.