Putting "URGENT" in the topic title does not help. Remember that people answering your questions here are just volunteers who do not have any obligation to you; read this:
Ease Up.
The API documentation for class java.net.InetAddress for
Java 1.4.2 mention this networking property, but the documentation for Java 1.3.1 does not. So most likely this setting does not exist in version 1.3.1.