FUUUU waarom werkt dit niet?

[COLOR= #0000BB]<?php[/COLOR]
[COLOR= #007700]}[/COLOR][URL="http://www.php.net/elseif"]elseif[/URL][COLOR= #007700]([/COLOR][COLOR= #0000BB]$mysqli[/COLOR][COLOR= #007700]->[/COLOR]num_rows[COLOR= #007700]([/COLOR][COLOR= #0000BB]$checkNaam[/COLOR][COLOR= #007700]) ==[/COLOR] [COLOR= #DD0000]1[/COLOR][COLOR= #007700]){[/COLOR]
[URL="http://www.php.net/echo"]echo[/URL] [COLOR= #DD0000]Deze gebruiker bestaat al<br> <a href="javascript:history.back(1)">Ga terug</a>[/COLOR][COLOR= #007700];
}[/COLOR][URL="http://www.php.net/elseif"]elseif[/URL][COLOR= #007700]([/COLOR][COLOR= #0000BB]$mysqli[/COLOR][COLOR= #007700]->[/COLOR]num_rows[COLOR= #007700]([/COLOR][COLOR= #0000BB]$checkEmail[/COLOR][COLOR= #007700]) ==[/COLOR] [COLOR= #DD0000]1[/COLOR][COLOR= #007700]){[/COLOR]
[URL="http://www.php.net/echo"]echo[/URL] [COLOR= #DD0000]Er bestaat al een gebruiker met dit email adres<br> <a href="javascript:history.back(1)">Ga terug</a>[/COLOR][COLOR= #007700];[/COLOR]
?>