HELP: can not get variable value from HTML form

I DON'T have this problem with my development machine until I deploy the code to the production. I am using window XP home edition. I tried both apache-2.0.45 and apache -1.3.27 with both php-4.3.1 and php-4.3.2. and none of them works. the phpinfo(); works fine without any problem. but I could not get the variable value from the html FORM. the test program is, the link is http://www.kuaitech.com/test.php <HTML> <?php $user="GUEST"; echo ($user); ?> <FORM> Please type your name: <BR> <INPUT TYPE=TEXT NAME="username"><BR><BR> <INPUT TYPE=SUBMIT VALUE="Submit"> </FORM> You typed: <?php echo ($username); ?> </HTML> As you can see, I can get the value for $user which is defined within the php code, but I can not get the value for $username from html form. Many thanks. Emmy