Property jython.home is not set. If you are running from inside the IDE go to Tools --> Options --> Advanced Options --> Building --> Jython and set the value of the Jython Home. If you are running from command line please specify a property -Djython.home=...path to your jython installation dir... Property jython.home points to a non-existent directory. If you are running from inside the IDE select your project, right click, select Properties from the popup and in the dialog type or browse to the path where your Jython installation resides. If you are running from command line please specify a property -Djython.home=...path to your jythn installation dir... Must set src.dir Must set build.dir Must set dist.dir Must set build.classes.dir Must set build.classes.excludes Must set dist.jar Must select some files in the IDE or set pythonc.includes Must select one file in the IDE or set run.script