Problem with php 4.2.3

Hi i was previously using php 4.2.2 and there's some of my php code that is not functioning on php 4.2.3 the code <a href="index.php?fuseaction=a_value">link</a> works perfect php versions older than 4.2.3 where, in my index.php, i have some code like if(isset($fuseaction)) { switch($fuseaction) { case 'a_value': include("the_file_treating_a_value.php"); break; } } else { include("login.php"); } it's the same principle as the fusebox technology used in Cold Fusion this code works perfect on older versions of php so, i'd be grateful if you could explain to me why i'm experiencing this problem with php 4.2.3 Thanks and regards Yogesh Mahadnac