I'd like to say something about the session.

Session in WIN32, I do not know why PHP4 processing absolute path is always problematic. Focus on the Extension_dir, Upload_tmp_dir and Session.save_path settings, no matter how you set it up, and then I set it./, so I can.
But the problem comes again. Session.save_path This path corresponds to the currently executing PHP file, so when you use session, if you change to another directory, then the session is gone.
Of course, these do not exist under Linux. Because Linux, can use/tmp.

So for this brother's question, I think I can do that. First, look at your PHP. INI content, Session.save_path should be changed to./. Then, there are some questions about your program, and I added some notes. You can try again.

<?php
Session_register ("abc"); You should assign a value to a variable before you perform some functions
$ABC = "ABCDEFG"; That means the sentence should be put in the front.
Header ("Location:go.php");

?>
//////////////////////////////////////////
go.php

<?php
Session_register ("abc"); This sentence is not necessary.
echo "You are". $abc. " \ n ";
?>