I believe this line (1048) in wakautils.pl contains a bug:
my %excluded_fields=map ($_=>1),@{$args{excluded_fields}||[]};
It should be
my %excluded_fields=map +($_=>1),@{$args{excluded_fields}||[]};
Otherwise adding fields to the spam_engine call in wakaba.pl will do all of nothing. since file and password really really need to be on there if you intend to post to your board, this is a bit of a problem.