Why not outlook?

This is my first post, and let me get to the issue straight away.

I was going through “Java 2: The Complete Reference” by Herbert Schildt, there is this chapter on java.lang, in which there is a discussion of the methods of a class called Runtime.

A method called exec() is introduced which can call other programs. It seems similar to what happens in when you type notepad in Start ----> Run. In here, if you pass notepad as an argument to the method it would invoke the program. Here is the example program that the book gives:

public class ExecDemo {

/**
* @param args the command line arguments
*/
public static void main(String[] args) {
// TODO code application logic here
Runtime r = Runtime.getRuntime();
Process p = null;

try {
p = r.exec("outlook");
p.waitFor();

} catch (Exception e) {
System.out.println("Error Opening outlook.");
}

System.out.println("Outlook Returned: " /*+ p.exitValue()*/);
}
}

It seems to work fine, but when I replace notepad with outlook.

p = r.exec("outlook");

It doesn’t work anymore. This is what I get in the output screen of my IDE (NetBeans):

So I commented off p.exitValue(), which is supposed to return 0 if the process (called) terminated normally or else it is supposed to return 1. The program degraded gracefully by calling on the exception:

The problem seems to be with the call to outlook. Does anyone know why it is unable to call outlook?