The problem is here :
$base = "bob","bob2";
In php, it means nothing.
The best way to do what you want is :
$n = $_GET['n'];
$base = array("bob", "bob2");
if (in_array($n, $base)) { echo "in the the base
"; } else { echo "not in base!
"; }
And please, don't use error_reporting(0) !