Problems with a IF statement with multiple POSTS in it

I seem to have a problem which I can't seem to figure out. I've made a simple index.php where I include all my files on conditions.

But I get an 500 error: PHP Parse error: syntax error, unexpected '{' in index.php on line 6

My code looks like this:

<?php
session_start();
$level = $_SESSION['Code'];
$functie = $_SESSION['cia'];

if (ISSET($_POST['projectmaken']) || ISSET($_POST['verstuurf']) {
    include 'NieuwProject.php';
}
else {
if ($level == 3 || $level == 4 || $functie == "supervisor") {
    include 'deadlineproject.php';
    }
else {
    include '/';
    }
}
?>

Does anyone know the problem here?

Thanks in advance!