Sorry for my english.

In Bug #23475: mktime() of dates before 1 jan 1970 gives a timestamp of "-3662"
In this case gives a timestamp of "-1"

Apache/2.0.45 (Win32) 
PHP/4.3.1
if $year<=1970 or $year>=2039
In linux? 

This code:
-------------------------------------------------
<?
if(!isset($year)) $year="2039";
$month="1";
$day="1";
$t=mktime ( 0, 0, 0, $month, $day, $year);
echo date("m-d-Y", $t)." -------- ".$t;
?>
--------------------------------------------------
--> 
Warning: mktime() [function.mktime]: Windows does not support negative values for this function in E:\Archivos de programa\Apache Group\Apache2\htdocs\k.php on line x

Thanks