$PHP_SELF no longer working

All of a sudden, code that had been working just fine for months stopped working. I called the host provider to see if they had made any changes at their end and they said, "No." All the pages (page1.php, page2.php, etc.) within one directory (protected) are password protected. The first line of each page in this directory is: <?php include("accesscontrol.php"); ?> The accesscontrol.php file is in the same directory as the protected pages. It checks to see if the user is already logged in. If not logged in it displays a form asking for user id and password. The form action is as follows: <form action="<?=$PHP_SELF?>" method="post" Up until today, after submitting the form with a password and user id, the accesscontrol.php page would evaluate the submitted password and id, and if correct, the original page would be displayed. Today, after submitting the form I get a 404 URL not found. The URL listed is as follows: /protected/h/protected/page1.php The problem is with the extra /protected/h/protected. I don't know where that is coming from. It never happened before today. Any ideas? Thanks, Jo Ann Comito