$mob->DoKnockback(?);

[Loxo]

a working version of the first script for comparison:

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

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 $ent (@clientlist)
	            {
					if($npc->CheckLoS($ent))
					{
	                    $npc->SignalClient($ent, 11111);
						quest::ze(10, "A gentle breeze passes through.");
						quest::stoptimer("windone");
					}
					else
					{
					}
	            }
	}
	elsif ($timer eq "windtwo")
	{
		my @clientlist = $entity_list->GetClientList();
	            foreach $ent (@clientlist)
	            {
					if($npc->CheckLoS($ent))
					{
						$ent->DoKnockback($npc, 2, 0);
						quest::ze(10, "A gust from the North sweeps through.");
						quest::stoptimer("windtwo");
					}
					else
					{
					}
	            }
	}
	elsif ($timer eq "windthree")
	{
		my @clientlist = $entity_list->GetClientList();
	            foreach $ent (@clientlist)
	            {
					if($npc->CheckLoS($ent))
					{
	                    $ent->DoKnockback($npc, 1, 0);
						quest::stoptimer("windthree");
						quest::settimerMS("constwind", 150);
						quest::ze(10, "The wind howls...");
					}
					else
					{
					}
	            }
	}
	elsif ($timer eq "constwind")
	{
	my $randomstopwind = int(rand(10));
		if ($randomstopwind < 9)
		{
			my @clientlist = $entity_list->GetClientList();
					foreach $ent (@clientlist)
					{
						if($npc->CheckLoS($ent))
						{
							$ent->DoKnockback($npc, 0.20, 0);
						}
						else
						{
						}
					}
		}
		else
		{
			quest::stoptimer("constwind");
			quest::ze(10, "The wind dies down");
		}
	}
	else
	{
	}
}

Just to verify, will...

elsif ($timer eq "windtwo")
	{
		my @clientlist = $entity_list->GetClientList();
	            foreach $ent (@clientlist)
	            {
					if($npc->CheckLoS($ent))
					{
						$ent->DoKnockback($npc, 2, 0);
						quest::ze(10, "A gust from the North sweeps through.");
						quest::stoptimer("windtwo");
					}
					else
					{
					}
	            }
	}

...work for validating a player is still in the zone, as it checks the list then checks LoS (which would report back a 0 for any player on the list no longer present?) for any client on the list each time the timers go off?