EJB deployment error when migrating to jboss 6.1

I am migrating from jboss 5.1 to 6.1. I have an ear which having some EJBs and a war. I am getting following error after deploying it in 6.1.

12:00:23,184 INFO  [PersistenceUnitDeployment] Starting persistence unit persistence.unit:unitName=ZServer.ear/#ZPersistCtx
12:00:23,204 ERROR [AbstractKernelController] Error installing to Start: name=persistence.unit:unitName=ZServer.ear/#ZPersistCtx state=Create: java.lang.ClassCastException: org.hibernate.ejb.HibernatePersistence cannot be cast to javax.persistence.spi.PersistenceProvider
        at org.jboss.jpa.builder.DefaultCEMFBuilder.build(DefaultCEMFBuilder.java:46) [:1.0.2-alpha-4]
        at org.jboss.as.jpa.scanner.HackCEMFBuilder.build(HackCEMFBuilder.java:49) [:6.1.0.Final]
        at org.jboss.jpa.deployment.PersistenceUnitDeployment.start(PersistenceUnitDeployment.java:275) [:1.0.2-alpha-4]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_26]
        .
        .
        .
        at org.jboss.profileservice.bootstrap.AbstractProfileServiceBootstrap.start(AbstractProfileServiceBootstrap.java:91) [:0.2.2]
        at org.jboss.system.server.profileservice.bootstrap.BasicProfileServiceBootstrap.start(BasicProfileServiceBootstrap.java:132) [:6.1.0.Final]
        at org.jboss.system.server.profileservice.bootstrap.BasicProfileServiceBootstrap.sta开发者_如何学Gort(BasicProfileServiceBootstrap.java:56) [:6.1.0.Final]
        at org.jboss.bootstrap.impl.base.server.AbstractServer.startBootstraps(AbstractServer.java:827) [jboss-bootstrap-impl-base.jar:2.1.0-alpha-6]
        at org.jboss.bootstrap.impl.base.server.AbstractServer$StartServerTask.run(AbstractServer.java:417) [jboss-bootstrap-impl-base.jar:2.1.0-alpha-6]
        at java.lang.Thread.run(Thread.java:662) [:1.6.0_26]

12:00:23,442 INFO  [EJBContainer] STARTED EJB: com.al.sqlgen.ejb.ResponseListnerMDBBean ejbName: ResponseListnerMDBBean
12:00:23,751 WARN  [TimerServiceContainer] EJBTHREE-2193: using deprecated TimerServiceFactory for restoring timers

I have following libs in ear.

dohan@mypc:~/usr/local/jboss-6.1.0.Final/server/all/deploy/ZServer.ear/lib> ls
antlr-2.7.6.jar                flex-messaging-remoting.jar
asm-attrs.jar                  hibernate3.jar
asm.jar                        hibernate-annotations.jar
cglib-2.1.3.jar                hibernate-commons-annotations.jar
commons-collections-2.1.1.jar  hibernate-entitymanager.jar
commons-io-1.4.jar             hibernate-tools.jar
commons-logging-1.1.jar        HsmSEE.jar
dom4j-1.6.1.jar                javassist.jar
ehcache-1.2.3.jar              jdbc2_0-stdext.jar
ejb3-persistence.2.jar         jta.jar

I tried changing class loading procedure as mentioned here but still getting same error. Appreciate if anyone can help me to solve this.

I removed the jars and did the changes proposed at mastertheboss.com/hibernate/…. It is working now. Thanks!