error occurs when closing josm

[jongleur1983@…]

What steps will reproduce the problem?
(reproduction untested)

1. copy a data layer containing data (e.g. fresh downloaded from osm)
2. exit josm without saving or updating

What is the expected result?
JOSM should exit without saving quietly, I think.

What happens instead?
Instead an error dialog box appears, asking for reporting the bug. After closing the box (no matter, what choice I used), one data layer is gone, but josm is not closed. I can repeat closing getting the same behaviour.

Please provide any additional information below. Attach a screenshot if
possible.

Repository Root: http://josm.openstreetmap.de/svn
Build-Date: 2010-07-22 01:31:57
Last Changed Author: stoecker
Revision: 3380
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
URL: http://josm.openstreetmap.de/svn/trunk
Last Changed Date: 2010-07-21 21:17:09 +0200 (Wed, 21 Jul 2010)
Last Changed Rev: 3380

Identification: JOSM/1.5 (3380 de)
Memory Usage: 72 MB / 483 MB (34 MB allocated, but free)
Java version: 1.6.0_18, Sun Microsystems Inc., OpenJDK Server VM
Operating system: Linux

Plugin: PicLayer (21706)
Plugin: measurement (21706)
Plugin: openstreetbugs (21706)
Plugin: osmarender (21774)
Plugin: turnrestrictions (21706)
Plugin: validator (22204)
Plugin: walkingpapers (21706)

java.lang.NullPointerException
	at org.openstreetmap.josm.data.AutosaveTask.setLayerFileName(AutosaveTask.java:113)
	at org.openstreetmap.josm.data.AutosaveTask.savelayer(AutosaveTask.java:149)
	at org.openstreetmap.josm.data.AutosaveTask.layerRemoved(AutosaveTask.java:216)
	at org.openstreetmap.josm.gui.MapView.fireLayerRemoved(MapView.java:148)
	at org.openstreetmap.josm.gui.MapView.removeLayer(MapView.java:360)
	at org.openstreetmap.josm.Main.exitJosm(Main.java:517)
	at org.openstreetmap.josm.gui.MainApplication$1.windowClosing(MainApplication.java:63)
	at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:349)
	at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:349)
	at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:349)
	at java.awt.Window.processWindowEvent(Window.java:1865)
	at javax.swing.JFrame.processWindowEvent(JFrame.java:290)
	at java.awt.Window.processEvent(Window.java:1823)
	at java.awt.Component.dispatchEventImpl(Component.java:4469)
	at java.awt.Container.dispatchEventImpl(Container.java:2163)
	at java.awt.Window.dispatchEventImpl(Window.java:2478)
	at java.awt.Component.dispatchEvent(Component.java:4295)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:604)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:275)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:200)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:185)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:177)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:138)