java.lang.IllegalArgumentException: Already listening to C:\Documents and Settings\is153249\My Documents\NetBeansProjects\JavaApplication6\test
        at org.openide.filesystems.FileUtil.addFileChangeListener(FileUtil.java:242)
        at org.netbeans.modules.java.api.common.SourceRoots$ProjectMetadataListener.add(SourceRoots.java:511)
        at org.netbeans.modules.java.api.common.SourceRoots$4.run(SourceRoots.java:257)
        at org.netbeans.modules.java.api.common.SourceRoots$4.run(SourceRoots.java:235)
        at org.openide.util.Mutex.readAccess(Mutex.java:285)
        at org.netbeans.modules.java.api.common.SourceRoots.getRootURLs(SourceRoots.java:235)
        at org.netbeans.modules.java.api.common.classpath.SourcePathImplementation.getResources(SourcePathImplementation.java:159)
        at org.netbeans.api.java.classpath.ClassPath.entries(ClassPath.java:295)
        at org.netbeans.modules.parsing.impl.indexing.PathRegistry.createResources(PathRegistry.java:520)
        at org.netbeans.modules.parsing.impl.indexing.PathRegistry.getPathIdToRoots(PathRegistry.java:479)
        at org.netbeans.modules.parsing.impl.indexing.PathRegistry.getRootsMarkedAs(PathRegistry.java:355)
        at org.netbeans.modules.parsing.spi.indexing.support.QuerySupport.getClasspathRoots(QuerySupport.java:416)
        at org.netbeans.modules.parsing.spi.indexing.support.QuerySupport.collectClasspathRoots(QuerySupport.java:375)
        at org.netbeans.modules.parsing.spi.indexing.support.QuerySupport.findRoots(QuerySupport.java:184)
        at org.netbeans.modules.csl.core.GsfTaskProvider$Work.run(GsfTaskProvider.java:258)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.IllegalArgumentException: Already listening to C:\Documents and Settings\is153249\My Documents\NetBeansProjects\JavaApplication6\test
        at org.openide.util.RequestProcessor.post(RequestProcessor.java:292)
        at org.netbeans.modules.csl.core.GsfTaskProvider.enqueue(GsfTaskProvider.java:173)
        at org.netbeans.modules.csl.core.GsfTaskProvider.setScope(GsfTaskProvider.java:120)
        at org.netbeans.modules.tasklist.impl.TaskManagerImpl.attachPushScanners(TaskManagerImpl.java:202)
        at org.netbeans.modules.tasklist.impl.TaskManagerImpl.doObserve(TaskManagerImpl.java:159)
        at org.netbeans.modules.tasklist.impl.TaskManagerImpl.access$000(TaskManagerImpl.java:73)
        at org.netbeans.modules.tasklist.impl.TaskManagerImpl$1.run(TaskManagerImpl.java:103)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:602)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1070)