Funny mktime bug??

Hi, I'm not sure why but the mktime function on my php installation consistently shows different values at erratic intervals... For eg when I call : mktime (0,0,0,1,1,1998) the result i get is either 883584000 or 883641600... I was trying to debug why my cookies will not be accepted by IE... a code block as such : --------- $myTime = mktime (0,0,0,1,1,1998); print "<br>My Time is $myTime"; echo date ("<br>M d Y H:i:s", $myTime); echo gmdate ("<br>M d Y H:i:s", $myTime); --------- results in these 2 different sets of results : 1) My Time is 883641600 Jan 01 1998 00:00:00 Jan 01 1998 08:00:00 2) My Time is 883584000 Jan 01 1998 00:00:00 Dec 31 1997 16:00:00 and the results are *consistently* one of these 2... there doesn't seem to be any ordering between the 2 result sets... they seem to interchange randomly... Would greatly appreciate it if anybody could tell me what's going on... Thanks Wong