It seems that PHP either is not ready to compare arrays or
it just compares different arrays wrongly saying they are
equal.

Just try this:

<?
   $array_1=array("1");
   $array_2=array("2");
   if($array_1!=$array_2)
    echo "Different\n";
   else
    echo "Equal\n";
?>

If  PHP is not ready to compare arrays or objects for the matter, it should
issue  an  error or a warning at least when you have error reporting set to
15.