Multiple user level problems

I have a site that has one login with multiple access levels stored in a database. The levels are; elite, excel, silver and bronze.
I have set up the rules for each one to allow if
Elite: <?php echo $_SESSION['level']; ?>=elite
Excel: <?php echo $_SESSION['level']; ?>=excel
Silver: <?php echo $_SESSION['level']; ?>=silver
Bronze: <?php echo $_SESSION['level']; ?>=bronze
I have set up the page rules so that when a user logs in it goes to the elite page. If the user level is elite all is well and the user can view that page. However if the user level is not elite it goes to the excel page.
If the user level is excel all is well and the user can view that page. However if the user level is not excel it goes to the silver page.
If the user level is silver all is well and the user can view that page. However if the user level is not silver it goes to the bronze page.
It works for the elite login but if anyone have a level below elite ie excel or silver I get this error on the excel page
Fatal error: Call to undefined function wa_auth_rulepasses() in /home/wwwextr/public_html/excel/index.php on line 3