Setup: MySQL 5.0.46 enterprise with Mysql connector 5.1.7 Jboss- 4.2.3 GA The are 2 Databases configured-JBossDB and AppDB. The *-ds.xml files have been configured to bind DefaultDS to Jboss DB and AppDS JNDI to AppDB Both use <local-tx-datasource> In a method call, 2 functions are being invoked 1. One function uses injected Entity manager (CMP) and calls em.persist and returns. 2. The other method uses EJB TimerService to create a timer - which in turn tries to create an entry in JBossDB While doing this, its throwing the following exception stack: EJBException -> IllegalStateException -> NestedSqlException -> Could not enlist in transaction on entering post-aware object I am new to EJB world and the JTA world. Is the above error because of a single transaction updating 2 different databases? Will using xa-datasource help in resolving this issue? thanks in advance Venu View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4207911#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...