use of @ operator to suppress errors

hi. i'm using error_reporting(0) and set_error_handler("MyErrorHandler") to manage my errors but I'm getting situations where a NOTICE error is thrown. For example if I refer to $_GET['this'] when there is no 'this' querystring key then i get the error. I've tried using @$_GET['this'] but it makes no difference. Is this normal? Thanks in advance. Ben p.s. PHP 4.3.4 on Windows 2003