Myeclipse 提示框问题

使用Myeclipse 时候只要一点文件或者文件夹，就弹出个小框框，提示java.lang.NullpPoint错误，请高手帮忙！！！解决问题，马上结贴！！！！An error has occurred. See error log for more details.
java.lang.NullPointerException
下面是errorLog里面的东西：java.lang.NullPointerException
at org.eclipse.emf.common.notify.impl.BasicNotifierImpl.eNotify(BasicNotifierImpl.java:280)
at org.eclipse.emf.common.notify.impl.NotifyingListImpl.dispatchNotification(NotifyingListImpl.java:267)
at org.eclipse.jem.internal.util.emf.workbench.ProjectResourceSetImpl$SynchronizedResourcesEList.dispatchNotification(ProjectResourceSetImpl.java:335)
at org.eclipse.emf.common.notify.impl.NotifyingListImpl.addUnique(NotifyingListImpl.java:300)
at org.eclipse.emf.common.util.AbstractEList.add(AbstractEList.java:307)
at org.eclipse.jem.internal.util.emf.workbench.ProjectResourceSetImpl$SynchronizedResourcesEList.add(ProjectResourceSetImpl.java:81)
at org.eclipse.jem.internal.util.emf.workbench.ProjectResourceSetImpl.createResource(ProjectResourceSetImpl.java:392)
at org.eclipse.wst.common.internal.emfworkbench.integration.ProjectResourceSetEditImpl.createResource(ProjectResourceSetEditImpl.java:48)
at org.eclipse.emf.ecore.resource.impl.ResourceSetImpl.demandCreateResource(ResourceSetImpl.java:239)
at org.eclipse.jem.internal.util.emf.workbench.ProjectResourceSetImpl.getResource(ProjectResourceSetImpl.java:693)
at org.eclipse.jst.jee.model.internal.JEE5ModelProvider.getModelResource(JEE5ModelProvider.java:155)
at org.eclipse.jst.jee.model.internal.EAR5ModelProvider.getModelObject(EAR5ModelProvider.java:50)
at org.eclipse.jst.j2ee.project.EarUtilities.getEARLibDir(EarUtilities.java:372)
at org.eclipse.jst.j2ee.internal.common.classpath.J2EEComponentClasspathContainer.getBaseEARLibRefs(J2EEComponentClasspathContainer.java:321)
at org.eclipse.jst.j2ee.internal.common.classpath.J2EEComponentClasspathContainer.update(J2EEComponentClasspathContainer.java:211)
at org.eclipse.jst.j2ee.internal.common.classpath.J2EEComponentClasspathContainer.install(J2EEComponentClasspathContainer.java:351)
at org.eclipse.jst.j2ee.internal.common.classpath.J2EEComponentClasspathInitializer.initialize(J2EEComponentClasspathInitializer.java:47)
at org.eclipse.jdt.internal.core.JavaModelManager.initializeContainer(JavaModelManager.java:2642)
at org.eclipse.jdt.internal.core.JavaModelManager.getClasspathContainer(JavaModelManager.java:1813)
at org.eclipse.jdt.core.JavaCore.getClasspathContainer(JavaCore.java:2652)