KPDF is usually good enough at printing documents, but sometimes it fails completely.
And there's nothing worse that having a document you need to print and not beign able to do it. To fix that situation i just added a small hack to KPDF version that will be released with KDE 3.5.7.
In that version there will be a PDF Options tab with a Force rasterization checkmark that will let you force KPDF to render each PDF page to an image and print the image instead convert PDF commands into PS commands. This is bad as you lose the vector side of having a PS, but in cases KPDF did show the document correctly, but printing failed, i think it will be a welcome addition.