Have you also added and configured the others subs needed to make this work?
sub calc_expire_date {
###################
my ($temp_date);
$temp_date = &date_to_unix($in{'ADStart'});
$temp_date = $temp_date + ($in{'duration'}*86400);
$in{'Expires'} = &get_date($temp_date);
}
sub calc_remove_date {
###################
my ($temp_date);
$temp_date = &date_to_unix($in{'Expires'});
$temp_date = $temp_date + ($in{'Expires'}+86400);
$in{'Remove_by'} = &get_date($temp_date);
}
Sometimes you just have to play around with the various autodelete options and test until you get it all working the way you need to.
Unoffical DBMan FAQ
http://webmagic.hypermart.net/dbman/