InitialContext needs some properties to work. AFAIK there is jndi.properties file inside appserv-rt.jar. you should try to pass theese parameters manualy in InitialContext's constructor as in this example:
http://www.java-tips.org/java-ee-tips/enterprise-java-beans/accessing-an-ejb-from-an-applet.html
Theese 2 system properties are also needed, but i'm not sure if it should be passes to the constructor:
-Dorg.omg.CORBA.ORBInitialHost=localhost
-Dorg.omg.CORBA.ORBInitialPort=3700