You should also confirm that the JNDI name you are using ("ejb/SimpleBeanJNDI") exists. The admin console (port 4848) has a JNDI browser: click on Application Server in the LH pane and there will be a button in the RH pane called "JNDI Browsing".
FWIW, I have successfully used this mechanism:
obj = ic.lookup(CustomerFacadeRemote.class.getName());
customerFacade = (CustomerFacadeRemote) obj;
where the Facade is the auto-created (by NB) EJB3 facade for the bean.
[for an EJB2 bean you would use "CustomerHome.glass.getName()"]
Since you aren't getting a ClassNotFoundException it's unlikely to be a jar file problem.
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