Esta forma es más fácil, creo...
Código PHP:
<?php
function date_diff($from, $to = null)
{
if (!is_integer($from))
{
$from = strtotime($from);
}
if ($to === null)
{
$to = time();
} elseif (!is_integer($to))
{
$to = strtotime($to);
}
$diff = $to - $from;
$return['days'] = floor($diff / (24 * 60 * 60));
$diff -= $return['days'] * 24 * 60 * 60;
$return['hours'] = floor($diff / (60 * 60));
$diff -= $return['hours'] * 60 * 60;
$return['minutes'] = floor($diff / (60));
$diff -= $return['minutes'] * 60;
$return['seconds'] = floor($diff);
return $return;
}
$dateFrom = "25-03-2005 14:20:00";
var_dump(date_diff($dateFrom));
?>