Hi David-
Something has changed: perhaps a folder was moved, a file was corrupt going in, etc.
If you're unsure what may have changed, try removing your PrintRipper Settings file in your Home folder: ~/Library/Preferences/PrintRipper Prefs/PrintRipper Settings.db
Remove this file from your PrintRipper Prefs folder and relaunch PrintRipper.
Also discussed @
http://www.allenchristopher.com/faq.html (see NilObject)