Global Variables Off

Ok, I have turned global vars off and I have replaced my old $HTTP_GET_VARS with $_GET[] but I seem to not get the values passed. I run the phpinfo and I see the variables being stored as _GET["variable_name"] Is calling $_GET["variable_name"] correct? If so, why would I not get the value? I use it in the following statement (checking if error_message is empty) : if ($_GET["error_message"]) Thanks Paul