ExtendedOperation() with TLS fails with javax.naming.NotContextException

Question

With JDK 1.4.2_12, I'm trying to access a Win2003 server with "ldap://<fqdn.server>:389" as Context.PROVIDER_URL. An SSL connection ("ldaps://<fqdn.server>:636") using the same keystore works fine. Testing it as a stand-alone app with TLS on a different machine also works fine (JDK 1.4.2_11) . Any help would be much appreciated as I'm completely flummoxed.
The line that throws the error is:
tls = (StartTlsResponse) ctx.extendedOperation(new StartTlsRequest());-Gregg
======================================
LdapContext ctx = null;
StartTlsResponse tls = null;
Hashtable env = new Hashtable(11);
env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
env.put("java.naming.ldap.version" , "3");
env.put("java.naming.ldap.derefAliases", "always");
env.put(Context.PROVIDER_URL, getLDAPURL());
if (useSSL()) env.put(Context.SECURITY_PROTOCOL, "ssl");
if (useSSL() || useTLS()) {
     java.lang.System.setProperty(JAVA_NET_KEYSTORE, getKeystore());
     java.lang.System.setProperty(JAVA_NET_KEYSTORE_PW, getKeystorePass());
     java.lang.System.setProperty(JAVA_NET_TRUSTSTORE, getKeystore());
     java.lang.System.setProperty(JAVA_NET_TRUSTSTORE_PW, getKeystorePass());
try {
     // Create initial context
     ctx = new InitialLdapContext(env, null);
     if (useTLS()) {
          tls = (StartTlsResponse) ctx.extendedOperation(new StartTlsRequest());
} catch (NamingException e) {
}======================================
Partial stack trace:
at javax.naming.ldap.InitialLdapContext.extendedOperation(InitialLdapContext.java:163)
at javax.naming.ldap.InitialLdapContext.getDefaultLdapInitCtx(InitialLdapContext.java:151)
   javax.naming.NotContextException: Not an instance of LdapContext

Answer 1

If it works on one machine and not another, then I hate to state the obvious, but you have to find out what is the difference between the two.
I have no idea why or how you get the "Not an instance of LdapContext". Unfortunately for you, this is where I can resort to my lame "I'm not a Java developer" excuse :-)
The only thing I can suggest is to remove the StartTLS stuff, and just see whether you can perform a basic LDAP operation over the ctx, such as a simple search.
Sorry that this is not much help.
Good luck.