JMS: lookup

I am passing from makes happy to jboss3.2.3. I have a problem with JMS. The code is following:
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String jndiUrl = "jnp://brusamo:1099";
java.util.Properties props = new Properties();
props.setProperty(Context.PROVIDER_URL, jndiUrl);
props.setProperty(InitialContext.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
props.setProperty (Context.URL_PKG_PREFIXES,"org.jboss.naming

rg.jnp.interfaces");

.....
...
Object tmp = ctx.lookup("ConnectionFactory");
tconFactory = (TopicConnectionFactory) tmp;
tcon = tconFactory.createTopicConnection();
During the lookup with ConnectionFactory I have always NullPointerException. I do not use res-ref or other in jboss-web.xml and/or jboss.xml the client is an applet. You can help me
Tanks