well i'm pretty sure he wants to get a variable that was passed to a page from another page, and obviously he is using the get method, so Norman Graham was correct in telling him, that he can either turn
register_globals = On // would leave off IMHO
or he can use
$GET['variablename']; // to access get variables
$POST['variablename']; // to access post variables
or he can use either
extract($GET); // to extract get variables to $variables
extract($POST); // to extract post variables to $variables