your mysql_query has a " before it, thus making it a string, and the string closes on the $menuDisplay var. so Remove the " from the start of $query var and close the $menuDisplay.
$sqlCommand = "SELECT id, linklabel FROM pages ORDER BY pageorder ASC";
$query = mysqli_query($myConnection, $sqlCommand) or die (mysqli_error());
$menuDisplay = "";
Try that, I'm not sure if there are any other errors, that's just what I noticed at quick glance.
EDIT:
Also get your hands on a PHP IDE, it will colorcode everything so you can see these kinds of errors. Google it, there are plenty of free ones out there.