HumanoidRootPart is not a valid member of RotateP?

Sorry if it seems like I am spamming however it worked fine yesterday and is now not working and is really frustrated from it.

local UserInputService = game:GetService("UserInputService")
local Player = game.Players.LocalPlayer
local isinrageof = nil
local ischatting = false
local line = 1
local istalking = false
local dialouges = nil

local function onInputBegan(input,gameProcessed)
 if input.UserInputType == Enum.UserInputType.Keyboard then
  local keyPressed = input.KeyCode
  if keyPressed == Enum.KeyCode.E then
   if isinrageof ~= nil and not istalking then
    if ischatting == false then
     line = 1
     ischatting = true
     dialouges = require(isinrageof.Lines)
     Player.Character.Humanoid.WalkSpeed = 0
     script.Parent.DialougeHolder.Dialouge.Text = ""
     script.Parent.DialougeHolder:TweenPosition(UDim2.new(.5,0,1,0),Enum.EasingDirection.Out,Enum.EasingStyle.Back,.5,true)
     wait(.5)
     local CurLine = dialouges[line]
     istalking = true
     for i = 1,#CurLine[1] do
      script.Parent.DialougeHolder.Dialouge.Text = string.sub(CurLine[1],0,i)
      wait(CurLine[2])
     end
     if CurLine[3] then
      CurLine[3]()
     end
     istalking = false
     line = line +1
    else
     local CurLine = dialouges[line]
     if line > #dialouges then
      script.Parent.DialougeHolder:TweenPosition(UDim2.new(.5,0,1.5,0),Enum.EasingDirection.Out,Enum.EasingStyle.Back,.5,true)
      Player.Character.Humanoid.WalkSpeed = 16
      dialouges = nil
      ischatting = false
     else
      local CurLine = dialouges[line]
      istalking = true
      for i = 1,#CurLine[1] do
       script.Parent.DialougeHolder.Dialouge.Text = string.sub(CurLine[1],0,i)
       wait(CurLine[2])
      end
      if CurLine[3] then
       CurLine[3]()
      end
      istalking = false
      line = line +1
     end
    end
   end
  end
 end
end

UserInputService.InputBegan:Connect(onInputBegan)

while true do
 wait()
 if ischatting == false then
  isinrageof = nil
  for i,v in pairs(workspace.NPCS:GetChildren()) do
   if(Player.Character.HumanoidRootPart.Position-v.HumanoidRootPart.Position).magnitude <= 5 then
    isinrageof = v
   end
  end
 end
end