Comment 3 for bug 147551

One line in your post may explain why it fails: The default (and therefore allowed by apparmor) place for created pdf's is $(HOME)/PDF. If this directory is not used (or is a symlink, just to add this), that means you've changed the default path in cups-pdf.conf, you'll need to apply this changes in the /etc/apparmor.d/usr.sbin.cupsd file, too.
The line:
> Mon Oct 1 10:14:51 2007 [ERROR] failed to set file mode for PDF file (non fatal)
> (/home/hunzikea/Desktop/Report_a_bug.pdf)
leeds me to the assumption, you did change the default-location for pdfs stored by cups-pdf, but you've forgotten to modify usr.sbin.cupsd-file to reflect these changes. If you e.g. want the created pdf-files to be placed on the Desktop, you'll need to change the lines:

 @{HOME}/PDF/ w,
 @{HOME}/PDF/* w,

into:

 @{HOME}/Desktop/ w,
 @{HOME}/Desktop/* w,

in the mentioned usr.sbin.cupsd file and restart the apparmor-service.