The org.jbpm.pvm.internal.tx.JtaTransaction class has JBoss specific code which does not run on Tomcat if JTA transaction is obtained via JOTM.

The code written is as below:

public static final String JNDINAME_USERTRANSACTION_JBOSS_GLOBAL = "UserTransaction";
public static final String JNDINAME_TRANSACTIONMANAGER_JBOSS_GLOBAL = "java:/TransactionManager";

But in Tomcat the required code is:
public static final String JNDINAME_USERTRANSACTION_JBOSS_GLOBAL = "java:comp/env/UserTransaction";

public static final String JNDINAME_TRANSACTIONMANAGER_JBOSS_GLOBAL = "java:comp/env/TransactionManager";

We have tested this using the above mentioned change and it works. But to make this work in any server we need one common approach so that it jBPM works in any server apart from JBoss. This should be externally configurable depending on the server used. I am in the process of creating one patch for this. I am ready to send that patch.