How do i fix this line of code? It is supposed to put your stand In front of you and punch

local combat = {}

function combat.Main(weld, Service, Stand, Anim, char, current)
    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(0,0,-3))

    local tween = Service:Create(weld, info, goal)
    tween:Play()

    local Animation = Stand.AnimationController:LoadAnimation(Anim)
    Animation:Play()

    Animation.Stopped:Connect(function()
        local goal2 = {}

        goal2.C0 = weld.Part0.CFrame:ToObjectSpace(weld.Part1.CFrame)
        goal2.C1 = weld.Part0.CFrame:ToObjectSpace(weld.Part1.CFrame * CFrame.new(-3, 1.5, 3))

        local back = Service:Create(weld, info, goal2)
        back:Play()
    end)

    local hitbox = Instance.new("Part", Stand)
    hitbox.Anchored = false
    hitbox.CanCollide = false
    hitbox.Size = char.HumanoidRootPart.Size
    hitbox.CFrame = Stand.HumanoidRootPart.CFrame * CFrame.new(0, 0, -2.5)
    hitbox.Transparency = 1

    local hitboxWeld = Instance.new("ManualWeld")
    hitboxWeld.Name = "HitboxWeld"
    hitboxWeld.Part0 = hitbox
    hitboxWeld.Part1 = Stand.HumanoidRootPart
    hitboxWeld.C0 = hitbox.CFrame:ToObjectSpace(Stand.HumanoidRootPart.CFrame)
    hitboxWeld.Parent = weld.Part0

    hitbox.Touched:Connect(function(hit)
        if hit.Parent:FindFirstChild("Humanoid") then
            if not hit:IsDescendantOf(char) then
                local enemyHum = hit.Parent:FindFirstChild("Humanoid")

                if current == 3 then
                    enemyHum:TakeDamage(5)
                else
                    enemyHum:TakeDamage(2)
                end

                hitbox:Destroy()
            end
        end
    end)
end

Output:ServerScriptService.StandHandler.Combat:7: attempt to index nil with 'Part0'

I tried to local it or delete it but nothing works, any help would be great.