Null pointer exception when trying to make gcode

[giantpune]

I have just extracted replicatorg and run the program for the first time, so default settings. My printer has not arrived yet, so replicatorg has never seen a printer. When I open a file from openscad and attempt to make gcode, nothing happens in the ui. In the console output, I see

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
        at replicatorg.app.ui.MainWindow.modelTooBig(MainWindow.java:664)
        at replicatorg.app.ui.MainWindow.runToolpathGenerator(MainWindow.java:628)
        at replicatorg.app.ui.modeling.ToolPanel$2.actionPerformed(ToolPanel.java:104)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
        at java.awt.Component.processMouseEvent(Component.java:6516)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3312)
        at java.awt.Component.processEvent(Component.java:6281)
        at java.awt.Container.processEvent(Container.java:2229)
        at java.awt.Component.dispatchEventImpl(Component.java:4872)
        at java.awt.Container.dispatchEventImpl(Container.java:2287)
        at java.awt.Component.dispatchEvent(Component.java:4698)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
        at java.awt.Container.dispatchEventImpl(Container.java:2273)
        at java.awt.Window.dispatchEventImpl(Window.java:2719)
        at java.awt.Component.dispatchEvent(Component.java:4698)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:747)
        at java.awt.EventQueue.access$300(EventQueue.java:103)
        at java.awt.EventQueue$3.run(EventQueue.java:706)
        at java.awt.EventQueue$3.run(EventQueue.java:704)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
        at java.awt.EventQueue$4.run(EventQueue.java:720)
        at java.awt.EventQueue$4.run(EventQueue.java:718)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:717)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)