I am testing a session bean by a client.
and I keep getting this error, I know my code should work because
I wrote the same code last week.

this is the error

xception in thread "main" javax.ejb.EJBTransactionRolledbackException: EntityManager must be access within a transaction
 at org.jboss.ejb3.tx.Ejb3TxPolicy.handleInCallerTx(Ejb3TxPolicy.java:87)
 at org.jboss.aspects.tx.TxPolicy.invokeInCallerTx(TxPolicy.java:130)
 at org.jboss.aspects.tx.TxInterceptor$Required.invoke(TxInterceptor.java:195)
 at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
 at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:76)
 at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
 at org.jboss.ejb3.stateless.StatelessInstanceInterceptor.invoke(StatelessInstanceInterceptor.java:62)
 at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
 at org.jboss.aspects.security.AuthenticationInterceptor.invoke(AuthenticationInterceptor.java:77)
 at org.jboss.ejb3.security.Ejb3AuthenticationInterceptor.invoke(Ejb3AuthenticationInterceptor.java:106)
 at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
 at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:46)
 at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
 at org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(AsynchronousInterceptor.java:106)
 at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
 at org.jboss.ejb3.stateless.StatelessContainer.dynamicInvoke(StatelessContainer.java:278)
 at org.jboss.aop.Dispatcher.invoke(Dispatcher.java:106)
 at org.jboss.aspects.remoting.AOPRemotingInvocationHandler.invoke(AOPRemotingInvocationHandler.java:82)
 at org.jboss.remoting.ServerInvoker.invoke(ServerInvoker.java:734)
 at org.jboss.remoting.transport.socket.ServerThread.processInvocation(ServerThread.java:560)
 at org.jboss.remoting.transport.socket.ServerThread.dorun(ServerThread.java:369)
 at org.jboss.remoting.transport.socket.ServerThread.run(ServerThread.java:165)
Caused by: javax.persistence.TransactionRequiredException: EntityManager must be access within a transaction
 at org.jboss.ejb3.entity.ManagedEntityManagerFactory.verifyInTx(ManagedEntityManagerFactory.java:150)

This is my main ... all i want to do is add an object in an table

public class KBClient {

 public static void main(String[] args) {

 KBClient c = new KBClient();
 ClassificationRemote r = c.lookupNewClassificationBean();
 KnowledgeBase first = new KnowledgeBase();
 first.setKnowledgeID(200);
 first.setKnowledgeName("AmerDemo");
 first.setKnowledgeCategory("Classification");
 first.setProjectID(new Project(88));
 first.setDeleted(0);
 r.addKnowledgeBase(first); //Exception occurs
 }

 private ClassificationRemote lookupNewClassificationBean() {
 try {
 Hashtable props = new Hashtable();
 props.put("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
 props.put("java.naming.factory.url.pkgs", "org.jboss.naming:org.jnp.interfaces");
 props.put("java.naming.provider.url", "localhost");
 Context c = new InitialContext(props);
 return (ClassificationRemote) c.lookup("ClassificationBeanFinal/remote");
 }
 catch(NamingException ne) {
 Logger.getLogger(getClass().getName()).log(Level.SEVERE,"exception caught" ,ne);
 throw new RuntimeException(ne);
 }
 }
}

and This is the function in the session bean

 @PersistenceContext private EntityManager em;

 public void addKnowledgeBase(KnowledgeBase kb){
 System.out.println("YAAAHOOOOOOO");
 em.persist(kb);
 }

I checked the JNDI tree as well ... everything is fine
the exception occurs when adding to the table in main.
Please help me !!!
Thanks