variables not being passed

Hi all I am having a weird problem with PHP in that it is not passing variables from page to page, either in a form or via URL. Here is an example of a test script I've run: <form method="post" action="testvariables.php"> // this file passes posts to itself Please type your name here:<br> <input type="text" name="username"<br><br> <input type="submit" value="Enter Name"> </form> <?php echo $username; ?> It doesn't come back with anything. This is true of all the applications that I have which work on my Linux server but which don't work under my Windows setup. It is odd, as I'm sure I've had this working earlier, but I did experience the same thing with one of the Beta's (I think it was beta 2) which was fixed in the next Beta. Has anyone either come across this or do you have any suggests as to how I can a) fix it or b) track down what the problem is? My spec is PHP 4.0.0, Windows 98, Apache 1.3.12 Thanks in advance Ade