$mob->DoKnockback(?);

[Loxo]

XS(XS_Mob_DoKnockback); /* prototype to pass -Wmissing-prototypes */
XS(XS_Mob_DoKnockback)
{
	dXSARGS;
	if (items != 4)
		Perl_croak(aTHX_ "Usage: Mob::DoKnockback(THIS, caster, pushback, pushup)");
	{
		Mob *		THIS;
		Mob *       caster;
		uint32		pushback = (uint16)SvUV(ST(2));
		uint32		pushup = (uint16)SvUV(ST(2));

		if (sv_derived_from(ST(0), "Mob")) {
			IV tmp = SvIV((SV*)SvRV(ST(0)));
			THIS = INT2PTR(Mob *,tmp);
		}
		else
			Perl_croak(aTHX_ "THIS is not of type Mob");
		if(THIS == NULL)
			Perl_croak(aTHX_ "THIS is NULL, avoiding crash.");

		if (sv_derived_from(ST(1), "Mob")) {
			IV tmp = SvIV((SV*)SvRV(ST(1)));
			caster = INT2PTR(Mob *,tmp);
		}
		else
			Perl_croak(aTHX_ "caster is not of type Mob");
		if(caster == NULL)
			Perl_croak(aTHX_ "caster is NULL, avoiding crash.");

		THIS->DoKnockback(caster, pushback, pushup);
	}
	XSRETURN_EMPTY;
}

I'm having trouble finding what will work as a variable for "caster." I have tried numerous variations on $mobid, $charid, $userid, just plain $mob/$npc/$client; but they all end up giving me an undefined report:

[02.14. - 06:09:54] Script error: qst1002524::EVENT_TIMER - Perl runtime error: Can't call method "DoKnockback" on an undefined value at quests/wood/northwind.pl line 45 (or 56).

This is the script I'm trying to use the object in, currently unsuccessfully using $character = $ent to try to specify, though I have tried various other mob/npc/client global variables as I'm not sure from the perl_mob.cpp who "caster" is supposed to be exactly:

sub EVENT_SPAWN
{
my $randomgail = (int(rand(1800)) + int(rand(1200)));
my $randomgust = (int(rand(1200)) + int(rand(600)));
my $randombreeze = (int(rand(600)) + int(rand(300)));
	quest::settimer("gail",31);
	quest::settimer("gust",53);
	quest::settimer("breeze",71);
}

sub EVENT_TIMER
{
my $delaywind = (int(rand(10)) + 1);
	if ($timer eq "breeze")
	{
		quest::settimer("windone",$delaywind);
		quest::ze(10, "The tree tops begin to rustle...");
	}
	elsif ($timer eq "gust")
	{
		quest::settimer("windtwo",$delaywind);
		quest::ze(10, "The tree tops begin to rustle...");
	}
	elsif ($timer eq "gail")
	{
		quest::settimer("windthree",$delaywind);
		quest::ze(10, "The tree tops begin to rustle...");
	}
	elsif ($timer eq "windone")
	{
		my @clientlist = $entity_list->GetClientList();
	            foreach $ent (@clientlist)
	            {
	                    $npc->CastSpell(697, $userid);
						quest::ze(10, "A gentle breeze passes through.");
						quest::stoptimer("windone");
	            }
	}
	elsif ($timer eq "windtwo")
	{
		my @clientlist = $entity_list->GetClientList();
	            foreach $ent (@clientlist)
	            {
					$character = $ent;
	                    $mob->DoKnockback($character, 15, 0);
						quest::ze(10, "A gust from the North sweeps through.");
						quest::stoptimer("windtwo");
	            }
	}
	elsif ($timer eq "windthree")
	{
		my @clientlist = $entity_list->GetClientList();
	            foreach $ent (@clientlist)
	            {
					$character = $ent;
	                    $mob->DoKnockback($character, 1, 0);
						quest::stoptimer("windthree");
						quest::settimerMS("constwind", 500);
						quest::ze(10, "The wind howls...");
	            }
	}
	elsif ($timer eq "constwind")
	{
	my $randomstopwind = int(rand(10));
		if ($randomstopwind < 9)
		{
			my @clientlist = $entity_list->GetClientList();
					foreach $ent (@clientlist)
					{
					$character = $ent;
						$mob->DoKnockback($character, 1, 0);
					}
		}
		else
		{
			quest::stoptimer("constwind");
			quest::ze(10, "The wind dies down");
		}
	}
	else
	{
	}
}

I've had success in other scripts defining a $variable = ($client) outside of the EVENT_TIMER so I could specify which client I wanted inside the timer, but with the $entity_list I don't think that will work, as I want these small knockbacks to hit each player in the zone.