Error that i didnt had before and i didnt change anything?

i get this error: Script:8: attempt to index field 'Parent' (a nil value)

local id = game.Workspace.Inmate:GetChildren()
local spawn = game.Workspace.InSpawns:GetChildren()
local player = script.Parent.Parent.Parent.Parent.Parent

function OnClicked()
    for d = 1, #id do
        if id[d].Value == "None" then
            script.Parent.Parent.Parent.Parent.UI.Id.Value = id[d].Name
            id[d].Value = player.Name
            script.Parent.Parent.Parent.Parent.UI.Team.Value = "Inmate"
            for u = 1, #spawn do
                if spawn["Spawn"..u] then
                    local spwn = spawn["Spawn"..u]
                    player.Character.Torso.CFrame = CFrame.new(spwn[u].Position.x, spwn[u].Position.y + 3, spwn[u].Position.z)



                end
            end
            local ui = script.Parent.Parent.Parent.Parent.UI:GetChildren()
            for o = 1,#ui do
                if ui[o].ClassName == "Frame" then
                script.Parent.Parent.Parent.Parent.UI.Character.Visible = false
                script.Parent.Parent.Parent.Parent.UI.Crafting.Visible = false
                ui[o].Visible = true
                end
            end
            script.Parent.Parent.Parent:remove()
        else
            script.Parent.Parent.Full.In.Visible = true
            wait(3)
            script.Parent.Parent.Full.In.Visible = false
        end
    end
end

script.Parent.MouseButton1Click:connect(OnClicked)