ServerScriptService.StandHandler:15: attempt to index nil with 'CFrame?'

I'm trying to make a Jojo's Bizzare Adventure game and I made a stand handling script (a regular script) and when I click "Q" to summon this comes up in the output.

               **"ServerScriptService.StandHandler:15: attempt to index nil with 'CFrame.'**

Here is the whole StandHandler Script. PS the error is in line 15.

local TweenService = game:GetService("TweenService")

local mainFolder = game.ReplicatedStorage.StandFolder
local Summon = mainFolder.RemoteEvents.Summon

Summon.OnServerEvent:Connect(function(player, isActive)
	local char = player.Character
	local hrp = char.HumanoidRootPart
	
	if isActive == true then
		local Stand = mainFolder.Models.Stand:Clone()
		local mainPart = Stand.PrimaryPart
		
		Stand.Parent = char
		mainPart.CFrame = hrp.CFrame
		
		local weld = Instance.new("ManualWeld")
		weld.Name = "Weld"
		weld.Part0 = mainPart
		weld.Part1 = hrp
		weld.C0 = mainPart.CFrame:ToObjectSpace(hrp.CFrame)
		weld.Parent = weld.Part0
		
		for i, bodyPart in pairs(Stand:GetChildren()) do
			if bodyPart:IsA("BasePart") and bodyPart ~= mainPart then
				local info = TweenInfo.new(0.45)
				local goal = {Transparency = 0}

				local tween = TweenService:Create(bodyPart, info, goal)
				tween:Play()
			end
		end
		
		local info = TweenInfo.new(0.5)
		local goal = {}
		goal.C0 = weld.Part0.CFrame:ToObjectSpace(weld.Part1.CFrame)
		goal.C1 = weld.Part0.CFrame:ToObjectSpace(weld.Part1.CFrame * CFrame.new(-3, 1.5, 3))
		
		local tween = TweenService:Create(weld, info, goal)
		tween:Play()
		
		local AnimControl = Stand.AnimationController
		local Idle = AnimControl:LoadAnimation(script.Animations.Idle)
		Idle:Play()
	else
		local Stand = char:WaitForChild("Stand")
		local mainPart = Stand.PrimaryPart
		
		if Stand then
			if Stand.PrimaryPart:WaitForChild("Weld") then
				local weld = Stand.PrimaryPart:WaitForChild("Weld")
				
				for i, bodyPart in pairs(Stand:GetChildren()) do
					if bodyPart:IsA("BasePart") and bodyPart ~= mainPart then
						local info = TweenInfo.new(0.45)
						local goal = {Transparency = 1}

						local tween = TweenService:Create(bodyPart, info, goal)
						tween:Play()
					end
				end

				local info = TweenInfo.new(0.5)
				local goal = {}
				goal.C0 = weld.Part0.CFrame:ToObjectSpace(weld.Part1.CFrame)
				goal.C1 = weld.Part0.CFrame:ToObjectSpace(weld.Part1.CFrame)

				local tween = TweenService:Create(weld, info, goal)
				tween:Play()
				
				tween.Completed:Connect(function()
					Stand:Destroy()
				end)
			end
		end
	end
end)