java.lang.AssertionError: Instance JBoss 6 started again without proper stop
   at org.netbeans.modules.j2ee.jboss4.ide.JBOutputSupport.reset(JBOutputSupport.java:249)
   at org.netbeans.modules.j2ee.jboss4.ide.JBOutputSupport.start(JBOutputSupport.java:119)
   at org.netbeans.modules.j2ee.jboss4.ide.JBStartRunnable.run(JBStartRunnable.java:147)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1411)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1991)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.AssertionError: Instance JBoss 6 started again without proper stop
   at org.openide.util.RequestProcessor.post(RequestProcessor.java:457)
   at org.netbeans.modules.j2ee.jboss4.ide.JBStartServer.startDeploymentManager(JBStartServer.java:191)
   at org.netbeans.modules.j2ee.deployment.impl.ServerInstance._start(ServerInstance.java:1462)
   at org.netbeans.modules.j2ee.deployment.impl.ServerInstance.startTarget(ServerInstance.java:1413)
   at org.netbeans.modules.j2ee.deployment.impl.ServerInstance.startTarget(ServerInstance.java:1218)
   at org.netbeans.modules.j2ee.deployment.impl.ServerInstance.start(ServerInstance.java:1095)
   at org.netbeans.modules.j2ee.deployment.impl.TargetServer.startTargets(TargetServer.java:547)
   at org.netbeans.modules.j2ee.deployment.devmodules.api.Deployment.deploy(Deployment.java:186)
   at org.netbeans.modules.j2ee.ant.Deploy.execute(Deploy.java:106)
   at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
   at sun.reflect.GeneratedMethodAccessor60.invoke(GeneratedMethodAccessor60.java:0)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
   at java.lang.reflect.Method.invoke(Method.java:601)
   at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
   at org.apache.tools.ant.Task.perform(Task.java:348)
   at org.apache.tools.ant.Target.execute(Target.java:390)
   at org.apache.tools.ant.Target.performTasks(Target.java:411)
   at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1399)
   at org.apache.tools.ant.Project.executeTarget(Project.java:1368)
   at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
   at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
   at org.apache.tools.ant.module.bridge.impl.BridgeImpl.run(BridgeImpl.java:285)
   at org.apache.tools.ant.module.run.TargetExecutor.run(TargetExecutor.java:539)
   at org.netbeans.core.execution.RunClassThread.run(RunClassThread.java:153)