[Imker] java.lang.NullPointerException

[gatwirival]

when trying to download files from files(local files).I get this error OS:linux(ubuntu) Version: v16.09.13 Stack trace:

    java.lang.NullPointerException
	at app.ImkerBase.downloadLoop(Unknown Source)
	at app.ImkerGUI$4.doInBackground(Unknown Source)
	at app.ImkerGUI$4.doInBackground(Unknown Source)
	at java.desktop/javax.swing.SwingWorker$1.call(SwingWorker.java:304)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.desktop/javax.swing.SwingWorker.run(SwingWorker.java:343)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:829)