java.lang.IllegalArgumentException: Already listening to R:\mc\doc
        at org.netbeans.modules.ruby.modules.project.rake.FileChangeSupport.addListener(FileChangeSupport.java:92)
        at org.netbeans.modules.ruby.spi.project.support.rake.SourcesHelper$SourcesImpl.listen(SourcesHelper.java:475)
        at org.netbeans.modules.ruby.spi.project.support.rake.SourcesHelper$SourcesImpl.getSourceGroups(SourcesHelper.java:409)
        at org.netbeans.modules.ruby.railsprojects.RailsSources$.run(RailsSources.java:110)
        at org.netbeans.modules.ruby.railsprojects.RailsSources$.run(RailsSources.java:101)
        at org.openide.util.Mutex.readAccess(Mutex.java:285)
        at org.netbeans.modules.ruby.railsprojects.RailsSources.getSourceGroups(RailsSources.java:100)
        at org.netbeans.spi.project.support.LookupProviderSupport$SourcesImpl.getSourceGroups(LookupProviderSupport.java:260)
        at org.netbeans.modules.ruby.railsprojects.ui.RailsLogicalViewProvider$RailsLogicalViewRootNode.setProjectFiles(RailsLogicalViewProvider.java:272)
        at org.netbeans.modules.ruby.railsprojects.ui.RailsLogicalViewProvider$RailsLogicalViewRootNode.<init>(RailsLogicalViewProvider.java:235)
        at org.netbeans.modules.ruby.railsprojects.ui.RailsLogicalViewProvider.createLogicalView(RailsLogicalViewProvider.java:135)
        at org.netbeans.modules.project.ui.ProjectsRootNode$ProjectChildren.logicalViewForProject(ProjectsRootNode.java:300)
        at org.netbeans.modules.project.ui.ProjectsRootNode$ProjectChildren.createNodes(ProjectsRootNode.java:261)
        at org.netbeans.modules.project.ui.ProjectsRootNode$ProjectChildren.createNodes(ProjectsRootNode.java:219)
        at org.openide.nodes.Children$Keys$KE.nodes(Children.java:1596)
        at org.openide.nodes.ChildrenArray.nodesFor(ChildrenArray.java:168)
        at org.openide.nodes.EntrySupport$Default$Info.nodes(EntrySupport.java:925)
        at org.openide.nodes.EntrySupport$Default.updateAdd(EntrySupport.java:505)
        at org.openide.nodes.EntrySupport$Default.setEntries(EntrySupport.java:345)
        at org.openide.nodes.Children$Keys$.run(Children.java:1490)
        at org.openide.util.Mutex$Exec.run(Mutex.java:1239)
        at org.openide.nodes.Children$ProjectManagerDeadlockDetector.execute(Children.java:1796)
        at org.openide.util.Mutex.postRequest(Mutex.java:1245)
        at org.openide.util.Mutex.postRequest(Mutex.java:1209)
        at org.openide.util.Mutex.postWriteRequest(Mutex.java:582)
        at org.openide.nodes.Children$Keys.applyKeys(Children.java:1499)
        at org.openide.nodes.Children$Keys.setKeys(Children.java:1443)
        at org.netbeans.modules.project.ui.ProjectsRootNode$ProjectChildren.propertyChange(ProjectsRootNode.java:318)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:276)
        at org.netbeans.modules.project.ui.OpenProjectList$.run(OpenProjectList.java:647)
        at org.netbeans.modules.project.ui.OpenProjectList$.run(OpenProjectList.java:646)
        at org.openide.util.Mutex$AWTWorker.run(Mutex.java:1370)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:199)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:177)
        at java.awt.Dialog$.run(Dialog.java:1045)
        at java.awt.Dialog$.run(Dialog.java:1097)
        at java.security.AccessController.doPrivileged(AccessController.java:0)
        at java.awt.Dialog.show(Dialog.java:1095)
        at java.awt.Component.show(Component.java:1422)
        at java.awt.Component.setVisible(Component.java:1375)
        at java.awt.Window.setVisible(Window.java:806)
        at java.awt.Dialog.setVisible(Dialog.java:985)
        at org.netbeans.modules.project.ui.OpenProjectList.open(OpenProjectList.java:526)
        at org.netbeans.modules.project.ui.OpenProjectList.open(OpenProjectList.java:464)
        at org.netbeans.modules.project.ui.actions.RecentProjects$MenuItemActionListener.actionPerformed(RecentProjects.java:206)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
        at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1220)
        at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1261)
        at java.awt.Component.processMouseEvent(Component.java:6041)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
        at java.awt.Component.processEvent(Component.java:5806)
        at java.awt.Container.processEvent(Container.java:2058)
        at java.awt.Component.dispatchEventImpl(Component.java:4413)
        at java.awt.Container.dispatchEventImpl(Container.java:2116)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4322)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:3986)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:3916)
        at java.awt.Container.dispatchEventImpl(Container.java:2102)
        at java.awt.Window.dispatchEventImpl(Window.java:2440)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)