Openning Karaf tab in hawt.io results in Exception in hawt.io

1. Uncomment line
admin=admin,admin
in the file jboss-fuse-6.1.0.redhat-007/etc/user.properties
2.Run jboss-fuse-6.1.0.redhat-007
3. Run the following commands:
features:install hawtio
4. Go to link http://localhost:8181/hawtio/index.html in browser and press Karaf tab.
The following error message is displayed in hawt.io:

Operation failed due to: java.nio.channels.OverlappingFileLockException at sun.nio.ch.SharedFileLockTable.checkList(FileLockTable.java:255) at sun.nio.ch.SharedFileLockTable.add(FileLockTable.java:152) at sun.nio.ch.FileChannelImpl.lock(FileChannelImpl.java:972) at java.nio.channels.FileChannel.lock(FileChannel.java:1052) at org.apache.karaf.util.properties.FileLockUtils.execute(FileLockUtils.java:66) at org.apache.karaf.util.properties.FileLockUtils.execute(FileLockUtils.java:94) at org.apache.karaf.admin.internal.AdminServiceImpl.execute(AdminServiceImpl.java:214) at org.apache.karaf.admin.internal.AdminServiceImpl.getInstances(AdminServiceImpl.java:347) at Proxy5bb0b44c_922c_4025_a950_8243a29ef131.getInstances(Unknown Source) at org.apache.karaf.admin.management.internal.AdminServiceMBeanImpl.getInstances(AdminServiceMBeanImpl.java:159) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:601) at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:111) at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:45) at com.sun.jmx.mbeanserver.MBeanIntrospector.invokeM(MBeanIntrospector.java:235) at com.sun.jmx.mbeanserver.PerInterface.getAttribute(PerInterface.java:83) at com.sun.jmx.mbeanserver.MBeanSupport.getAttribute(MBeanSupport.java:206) at javax.management.StandardMBean.getAttribut