WSM-02120 : Unable to connect to the policy access service (Oracle BI Publisher 11g)

I noticed this exception when starting up my Admin Server for Oracle's BI Publisher:

oracle.wsm.policymanager.PolicyManagerException: WSM-02120 : Unable to connect to the policy access service.
        at oracle.wsm.policymanager.BeanFactory.getInitialContext(BeanFactory.java:753)
        at oracle.wsm.policymanager.BeanFactory.getJndiObj(BeanFactory.java:780)
        at oracle.wsm.policymanager.BeanFactory.lookupJndiObj(BeanFactory.java:1061)
        at oracle.wsm.policymanager.BeanFactory.getDocumentManagerBeanEJB(BeanFactory.java:700)
        at oracle.wsm.policymanager.BeanFactory.getBeanEJB(BeanFactory.java:544)
        at oracle.wsm.policymanager.BeanFactory.getBean(BeanFactory.java:433)

...

which was caused by the following:

Caused By: javax.naming.CommunicationException [Root exception is java.net.ConnectException: t3s://adminhost.domain.com,adminhost.domain.com:9804: Destination unreachable; nested exception is:

        java.net.ConnectException: Connection refused; No available router to destination]

        at weblogic.jndi.internal.ExceptionTranslator.toNamingException(ExceptionTranslator.java:40)

        at weblogic.jndi.WLInitialContextFactoryDelegate.toNamingException(WLInitialContextFactoryDelegate.java:792)

        at weblogic.jndi.WLInitialContextFactoryDelegate.getInitialContext(WLInitialContextFactoryDelegate.java:368)

        at weblogic.jndi.Environment.getContext(Environment.java:315)

        at weblogic.jndi.Environment.getContext(Environment.java:285)

        at weblogic.jndi.WLInitialContextFactory.getInitialContext(WLInitialContextFactory.java:117)

        at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:684)

To prevent this exception, I changed the deployment target of wsm-pm from AdminServer,bi_cluster to just bi_cluster:

1. Logon to the WebLogic Console.
2. Click Deployments.
3. Find 'wsm-pm' in the list and click on it.
4. Click the Targets tab.
5. Click Lock & Edit.
6. Select the checkbox next to 'wsm-pm' and click the 'Change Targets' button.
7. Uncheck 'AdminServer'. Make sure the cluster is selected and 'All servers in the cluster'
8. Click 'Yes' and then 'Activate Changes'

Finally restart your admin server and managed servers.