This should work if you put it in the global_npc.pl file. the 12345 is whatever itemID (Untested of course)...
this also will not allow pets to get the item...
	Code:
	sub EVENT_SPAWN{
if ($mlevel >= 35)
	{
		return unless $npc->GetLoottableID();
		if (int(rand(100) + 1) >= 99) {
		{
			$npc->AddItem(12345,1,0);
			
		}
	  }
    }
}