To fix this y2k problem, you need to add the line 

$year += 1900;

to the code.

Replace the following code in chat.cgi (Around line 204):

#
# We use the current date and time
# in the program
#
($min, $hour, $day, $mon, $year) =
    (localtime(time))[1,2,3,4,5];
$mon++;
if (length($min) < 2) {
    $min = "0" . $min;
}
$ampm = "AM";
$ampm = "PM" if ($hour > 11);
$hour = $hour - 12 if ($hour > 12);
$current_date_time =
    "$mon/$day/$year $hour:$min $ampm";

With 

#
# We use the current date and time
# in the program
#
($min, $hour, $day, $mon, $year) =
    (localtime(time))[1,2,3,4,5];
$mon++;
if (length($min) < 2) {
    $min = "0" . $min;
}
$ampm = "AM";
$ampm = "PM" if ($hour > 11);
$hour = $hour - 12 if ($hour > 12);
$year += 1900; 
$current_date_time =
    "$mon/$day/$year $hour:$min $ampm";