The exception generated is:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at com.jidesoft.swing.FastGradientPainter.createGradientTile(Unknown Source)
at com.jidesoft.swing.FastGradientPainter.drawGradient(Unknown Source)
at com.jidesoft.swing.JideSwingUtilities.fillGradient(Unknown Source)
at com.jidesoft.plaf.office2007.Office2007Painter.fillBackground(Unknown Source)
at com.jidesoft.status.MemoryStatusBarItem$e_.paintComponent(Unknown Source)
at javax.swing.JComponent.printComponent(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.print(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.printChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.print(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.printChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.print(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.printChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.print(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.printChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.print(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.printChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.print(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.printChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.print(Unknown Source)
at java.awt.GraphicsCallback$PrintCallback.run(Unknown Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.print(Unknown Source)
at org.freehep.graphicsio.exportchooser.AbstractExportFileType.exportToFile(AbstractExportFileType.java:253)
at org.freehep.graphicsio.exportchooser.AbstractExportFileType.exportToFile(AbstractExportFileType.java:282)
at com.lorainelab.image.exporter.HeadLessExport.headlessComponentExport(HeadLessExport.java:72)
at com.lorainelab.image.exporter.ExportDialog.completeSaveButtonAction(ExportDialog.java:461)
at com.lorainelab.image.exporter.ExportDialog.lambda$showFileDialog$13(ExportDialog.java:357)
at com.lorainelab.image.exporter.ExportDialog$$Lambda$321/1971006213.accept(Unknown Source)
at java.util.Optional.ifPresent(Unknown Source)
at com.lorainelab.image.exporter.ExportDialog.showFileDialog(ExportDialog.java:349)
at com.lorainelab.image.exporter.ExportDialog.saveAsButtonActionPerformed(ExportDialog.java:326)
at com.lorainelab.image.exporter.ExportDialogGui.lambda$addMainPanel$1(ExportDialogGui.java:72)
at com.lorainelab.image.exporter.ExportDialogGui$$Lambda$242/463759298.actionPerformed(Unknown Source)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)