CUPS, the Common Unix Printing System, is b0rked in the standard Jaunty 9.04 release. Which is less than ideal when you want to print directly to PDF.
You can use “Print to File” and change from PostScript to PDF, and this will work, but I just wanted to use the PDF virtual printer, so did a bit of research and fixed it. Turns out cups is fine, but the AppArmour profile for cupsd was busted, so all we need to do is to tell AppArmour to just moan about cups-pdf instead of shutting it down due to the wonky profile.
From the console enter the following.
r3dux@r3dux-laptop:~$ sudo aa-complain
Please enter the program to switch to complain mode: cupsd
Setting /etc/apparmor.d/usr.sbin.cupsd to complain mode.
r3dux@r3dux-laptop:~$ sudo /etc/init.d/cups restart
* Restarting Common Unix Printing System: cupsd
[ OK ]
FiXX0r3d. Or smth.
Source (defunct as of 12/2013): http://linuxmoc.wordpress.com/2008/11/27/printing-to-pdf-broken-in-ubuntu-intrepid/
P.S. You can also fix the problem by disabling the AppArmour profile instead of putting the profile for cupsd to complain mode, full details given at source page above.