[Cripp]

sub EVENT_SAY
{

	if($text=~/hail/i)
	{
		if (!defined $aflag)
		{
			quest::setglobal("aflag", 1, 5, "F");
			quest::say("Now Flagged.");
		}
		if (defined $aflag)
		{
			quest::say("You are already flagged.");
		}
	}
}

try this...

edit: Moved to Quests::Q&A
edit2: Dont forget to set qglobals to 1 for the npc in npc_types table.