Calling lookup on the "TopicConnectionFactory" name is giving me the following error:

--- error output from ejb client on separate node ---
javax.naming.CommunicationException: Can't find SerialContextProvider

--- line causing error ---
topicConnectionFactory = (TopicConnectionFactory) ctx.lookup("TopicConnectionFactory");

--- my jndi.properties file ---
--- the provider is where my jboss server is running ---

java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory
java.naming.provider.url=jnp://192.168.0.10:1099
java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces

--- in my classpath ---
E:\acais>java -classpath E:\acais\conf\jndi.properties;c:\j2sdkee1.3.1\lib\j2ee.
jar;E:\acais\libs\log4j.jar;E:\acais\libs\NetComponents.jar;E:\acais\libs\acais-
client.jar;E:\acais\libs\oswego-concurrent.jar;E:\acais\libs\jboss.jar;E:\acais\
libs\jbossmq-client.jar;E:\acais\libs\jnp-client.jar;E:\acais\libs\jaas.jar;E:\a
cais\libs\jboss-client.jar;E:\acais\libs\jbosssx-client.jar com.neuroquest.cais.
clients.fielder.Fielder

Any help much appreciated.