Why am I getting this error with R15 people, but not R6 people?

I have tried to make a zombie script that can even chase R15 people. but for some reason ROBLOX can't detect a character. This works with R6, but not with R15.

Here's the script:

players = nil; 
dummy = script.Parent
currentPlayerFollowing = nil; 

while wait(0.1) do 
 players = game.Players:GetChildren(); 
 for _, player in pairs(players) do
    local character = game.Workspace:FindFirstChild(player.Name)
  if (player ~= nil and (math.abs(character.PrimaryPart.Position.X - dummy.Torso.Position.X)) <= 20) then 
   currentPlayerFollowing = player; 
  end
 end

 if (currentPlayerFollowing ~= nil) then 
    dummy.Humanoid.WalkToPoint = currentPlayerFollowing.Character.Torso.Position 
end
end

And here's the error I keep getting for R15 people:

21:25:55.173 - Workspace.Minion. .FollowScript:9: attempt to index local 'character' (a nil value) 21:25:55.174 - Stack Begin 21:25:55.175 - Script 'Workspace.Minion. .FollowScript', Line 9 21:25:55.176 - Stack End

It would be highly apprieciated if someone could help me out with this. Thanks!

EDIT: All I needed to do was add another wait since the character does not spawn instantly, it's solved!