Newbie session registration question

Hi there, I was using sessions to store username, password & database info for oracle logins. Nothing in my scripts changed, yet the session variables were no longer being passed in. We stopped/restarted the apache server with no results. a standard html passes in username, password & database via POST to this php file: <? session_start(); session_register('username'); session_register('password'); session_register('db'); $connection = OCILogon($username,$password,$db); if ($connection == false){ echo "login failed.<br>"; exit; } if (isset($username)){ echo "username successfully set"; } //bla bla bla OCILogoff($connection); ?> The script will echo "username successfully set." There is a link to a new page with this session script: <? session_start(); session_register('username'); session_register('password'); session_register('db'); echo "username=$username<br>pass=$password<br>db=$db"; $connection = OCILogon($username,$password,$db); if ($connection == false){ echo "login failed.<br>"; echo "debug info: <br> username=$username<br>password=$password<br>db=$db"; echo 'now destroying session.'; session_destroy(); exit; } ?> I get username= pass= db= ...in other words, the session variables act undefined. Why would this happen abruptly? I did not change any code in this part of the php file for weeks. Any help is appreciated! Paul