I use it fairly often, a few things to check althought you seem to have it sorted.
you set up a cups printer?
any jobs stuck in the queue? example:
http://imgur.com/eJId3then the output location is set in etc/cups/cups-pdf.conf. I made a PDF directory in home so I edited as
## CUPS-PDF output directory
## special qualifiers:
## ${HOME} will be expanded to the user's home directory
## ${USER} will be expanded to the user name
## Add for Fedora (~/.config/user-dirs.dirs)
## ${DESKTOP} will be expanded to the user's desktop directory
## in case it is an NFS export make sure it is exported without
## root_squash!
### Default: /var/spool/cups-pdf/${USER}
#Out /var/spool/cups-pdf/${USER}
#Out ${DESKTOP}
Out ${HOME}/PDF
using pclos2010 updated and cups-pdf 2.5.0 which seems to be the latest in the repo.