Exception Can't find a persistence unit named 'null'

[purnima na]

Hi,

The application works fine in Jboss 4.3.When migrating the application from Jboss 4.3 to Jboss 6,I am getting the below exception
I have added

metadata-complete="true"

in web.xml and renamed persistence.xml to some other name.Still the below error is not resolved.

Caused by: org.jboss.deployers.spi.DeploymentException: Error creating web module vfs:///C:/BupaEnv/EnterprisePlatform-4.3.0.GA_CP04/jboss-as/server/default/deploy/quicksilver.war
at org.jboss.deployers.spi.DeploymentException.rethrowAsDeploymentException(DeploymentException.java:49) [:2.2.2.GA]
at org.jboss.web.deployers.AbstractWarDeployer.deployWebModule(AbstractWarDeployer.java:810) [:6.1.0.Final]
at org.jboss.web.deployers.AbstractWarDeployer.deploy(AbstractWarDeployer.java:481) [:6.1.0.Final]
... 47 more
Caused by: java.lang.IllegalArgumentException: Can't find a persistence unit named 'null' in AbstractVFSDeploymentContext@13067275{vfs:///C:/BupaEnv/EnterprisePlatform-4.3.0.GA_CP04/jboss-as/server/default/deploy/quicksilver.war}
at org.jboss.jpa.resolvers.BasePersistenceUnitDependencyResolver.resolvePersistenceUnitSupplier(BasePersistenceUnitDependencyResolver.java:107) [:1.0.2-alpha-4]
at org.jboss.web.deployers.AbstractWarDeployer.deployWebModule(AbstractWarDeployer.java:791) [:6.1.0.Final]
... 48 more

Any ideas on how to get beyond this?

Thanks