LDAP problem

[Adam Hardy]

I'm using javax.naming.* to access an LDAP server. This is my code, and I don't understand the output showing the errors:

try
{
    com.sun.jndi.ldap.LdapCtxFactory obj1 = 
        new com.sun.jndi.ldap.LdapCtxFactory();
    out.println("instantiated LdapCtxFactory<BR>");
    Hashtable hashSetup = new Hashtable();
    hashSetup.put(Context.INITIAL_CONTEXT_FACTORY, 
        "com.sun.jndi.ldap.LdapCtxFactory");
    hashSetup.put(Context.PROVIDER_URL, strURLName);
    objDirContext = new InitialDirContext(hashSetup);
    out.println("created context<BR>");
}
catch (Exception objE)
{
    out.println(objE.getMessage());
}

the output looks like this:
instantiated LdapCtxFactory
Cannot instantiate class: com.sun.jndi.ldap.LdapCtxFactory
Why?!!!
as you can see, i can instantiate the LdapCtxFactory as a plain old class, but when I try to use it to create a context instance, it falls over.
Can anybody tell what stupid thing i'm doing wrong?
thanks
Adam