java.lang.AssertionError: Config file config/Modules/org-netbeans-modules-web-client-tools-firefox.xml must be already removed or marked for remove.
        at org.netbeans.modules.autoupdate.services.ModuleDeleterImpl.removeModuleFilesInCluster(ModuleDeleterImpl.java:294)
        at org.netbeans.modules.autoupdate.services.ModuleDeleterImpl.removeModuleFiles(ModuleDeleterImpl.java:281)
        at org.netbeans.modules.autoupdate.services.ModuleDeleterImpl.markForDelete(ModuleDeleterImpl.java:165)
        at org.netbeans.modules.autoupdate.services.OperationSupportImpl$ForUninstall.doOperation(OperationSupportImpl.java:395)
        at org.netbeans.api.autoupdate.OperationSupport.doOperation(OperationSupport.java:67)
        at org.netbeans.modules.autoupdate.ui.wizards.UninstallStep.handleAction(UninstallStep.java:192)
        at org.netbeans.modules.autoupdate.ui.wizards.UninstallStep.doAction(UninstallStep.java:152)
        at org.netbeans.modules.autoupdate.ui.wizards.UninstallStep.access$000(UninstallStep.java:67)
        at org.netbeans.modules.autoupdate.ui.wizards.UninstallStep$1.propertyChange(UninstallStep.java:126)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:333)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:270)
        at java.awt.Component.firePropertyChange(Component.java:7277)
        at org.netbeans.modules.autoupdate.ui.wizards.OperationPanel.access$000(OperationPanel.java:61)
        at org.netbeans.modules.autoupdate.ui.wizards.OperationPanel$1.run(OperationPanel.java:81)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:602)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1084)
Caused: org.openide.util.RequestProcessor$FastItem: task failed due to: java.lang.AssertionError: Config file config/Modules/org-netbeans-modules-web-client-tools-firefox.xml must be already removed or marked for remove.