Fatal Error help..

[MxpUnk]

Hey everyone, i'm re-coding a register page, and i've run into this error:

Fatal error: Call to a member function on a non-object in /home/cjnalsn1/public_html/site/register.php on line 11

and i went to find it on line 11, and saw the error, so I fixed it so it would connect right, but i am still getting the same error. Anyone know?

lines that its saying the error is on:
[code]
}
$name_check = $db_object->query("SELECT username FROM members WHERE username = '".$_POST['username']."'");
if (DB::isError($name_check)) {
        die($name_check->getMessage());
    }
$name_checkk = $name_check->numRows();
    if ($name_checkk != 0) {
        die('Sorry, the username: <strong>'.$_POST['username'].'</strong> is already in use, please choose a new username, and try again.');
    }[/code]