Own ErrorHandler but standard ErrorMsg

Hi! I've got a little Problem with my ErrorHandler. set_error_handler('ErrorHandler'); is executed on top of my script. Right after it the ErrorHandler function. After the ErrorHandler function there is a require('foo.php'); foo.php does not exist, so there should be an error message thrown out from my ErrorHandler - but the error message which i get is the standard-php error message. My ErrorHandler function works really fine and i only get the php-standard error from not existing includes or requires. Does anyone know how to solve this? error_reporting is set to 2039 in php.ini Thanks for helping! malte