Exception occurred while open the project that moved to another folder . This occurred if jnlp file opend in editor before close the project and move .

NetBeans build:
NetBeans IDE 5.0 Beta Build200509261930
JNLP Plug-in build:
17-Oct-2005 14:28:01

Steps:
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1. Create a new Java Application(JavaApplication1) or open an existing one .
2. Select this application in Projects View , right click mouse and invoke "Enable Java Web Start" from contextual menu . The jnlp file will be opened in the JNLP Editor
3. Close the project from menu "File" -- > "Close JavaApplication1" . The project and the jnlp file will be closed.
4. Move the project folder to another foler
5. Open the project from new folder using menu "File" -- > "Open Project..."

The exception thrown and the project can't be opend.

java.lang.AssertionError: DataObject must exist for MasterFileObject@136681[file:/C:/Documents%20and%20Settings/Administrator/TestProject/TestProject.jnlp]
at org.netbeans.modules.project.ui.ProjectUtilities$1.open(ProjectUtilities.java:74)
at org.netbeans.modules.project.ui.ProjectUtilities.openProjectFiles(ProjectUtilities.java:409)
at org.netbeans.modules.project.ui.OpenProjectList.open(OpenProjectList.java:176)
at org.netbeans.modules.project.ui.actions.OpenProject.actionPerformed(OpenProject.java:86)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1849)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2169)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:234)
at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:231)
at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:231)
at java.awt.Component.processMouseEvent(Component.java:5488)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3126)
at java.awt.Component.processEvent(Component.java:5253)
at java.awt.Container.processEvent(Container.java:1966)
at java.awt.Component.dispatchEventImpl(Component.java:3955)
at java.awt.Container.dispatchEventImpl(Container.java:2024)
at java.awt.Component.dispatchEvent(Component.java:3803)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4212)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3892)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3822)
at java.awt.Container.dispatchEventImpl(Container.java:2010)
at java.awt.Window.dispatchEventImpl(Window.java:1774)
at java.awt.Component.dispatchEvent(Component.java:3803)
[catch] at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)