No JTA TransactionManager found when using JBPM 5 with IBM Websphere Application Server

Issue

• Why are we getting the following exception intermittently while running the jBPM 5 process during newStatefulKnowledgeSession creation?

[2013-04-24 12:30:19,932] DEBUG [WebContainer : 1] [90OLBPRD:47407f93-6070-4883-98aa-a7302709bed5:eP ARI:] org.drools.persistence.jta.JtaTransactionManager No JTA TransactionManager found at fallback JNDI location [java:comp/TransactionManager]
javax.naming.NameNotFoundException: Name "comp/TransactionManager" not found in context "java:".
  at com.ibm.ws.naming.ipbase.NameSpace.lookupInternal(NameSpace.java:1178)
  at com.ibm.ws.naming.ipbase.NameSpace.lookup(NameSpace.java:1095)
  at com.ibm.ws.naming.urlbase.UrlContextImpl.lookup(UrlContextImpl.java:1235)
  at com.ibm.ws.naming.java.javaURLContextImpl.lookup(javaURLContextImpl.java:395)
  at com.ibm.ws.naming.java.javaURLContextRoot.lookup(javaURLContextRoot.java:221)
  at com.ibm.ws.naming.java.javaURLContextRoot.lookup(javaURLContextRoot.java:161)
  at javax.naming.InitialContext.lookup(InitialContext.java:436)
  at org.drools.persistence.jta.JtaTransactionManager.findTransactionManager(JtaTransactionManager.java:101)