I am trying to create a PDF with PrinterSwitch, but when printing nothing seems to happen (MacOS X)

Currently, you do not get an error message when defining an illegal path on Mac OS X (e.g. you're pointing to a user name or folder name that does not exist on the volume, or to a path where the user doesn't have rights to create files.)
To avoid this, make sure valid path is used.

If you want to use path names that will always be valid, use something like /tmp/ or /var/tmp/ for absolute path names, or ~/Desktop/ or ~/Documents for user directory-based path names.