basically your lookup is broken right? happened to me too. the jndi name changed to <deployment_name>//..
you can sure by looking at the jmx-console. in case of the 'default' jboss server go to http://localhost/jmx-console. click on 'service=JNDIView'. now invoke the list() method and search for your bean look at the exact namespace under which it is deployed. if you don't see your bean here . . . that's another problem.
Thanks for your reply, Fakeer.
Prior to post my S.O.S here, I had checked with JNDI view on the JMX Console, being aware of the syntaxical changes in JNDI reference in JBOSS4. In fact, I am using the same default JNDI name for invoking the same session bean from a client class without having problem.
In the meantime, I tried to let the scheduler depend on other evident MBEANs, and had no problem. As a practical alternative , I let the scheduler depend on the persistance unit associated to the deployment unit as here below and confirmed that it works.
I understand that the dependency assignment normaly waits for a MBEAN, So, now, I am asking to myself if POJO EJB3 classes cannot be refered to as MBEAN.
Anyway, thanks a lot for your suggestion, and your any further idea about here above will be welcome.