Changing a NPC race in Perl, please help

[rixcraven]

ub EVENT_SPAWN {
#Set a random timer between 5 and 30
my $StartMove = int(rand(25)) + 5;
quest::settimer("roam", $StartMove);
}

sub EVENT_TIMER {
if ($timer eq "roam") {
quest::stoptimer("roam");
plugin::RandomRoam(100, 100);
my $NextMove = int(rand(25)) + 5;
quest::settimer("roam", $NextMove);
}
sub EVENT_COMBAT {
quest::npcfeature("race", 454);


}
sub EVENT_SLAY {
quest::npcfeature("race", 1);
}
}

This script is supposed to change an NPC, from human female into a Werewolf when she is attacked..
Could anyone shed any light on why it isn't working???
What happens is, she changes into a human female??? not a werewolf..
please help