How to fix: attempt to index global 'n' (a number value) ?

I'm trying to put a gui's adornee on the closest part. The part is spawned when people click a button. I tried to use this script:

local plrName = script.Parent.Name
local rK = game.Players:GetPlayerFromCharacter(script.Parent).PlayerGui:WaitForChild("RKeyGen")

while true do
    for i, v in pairs(game.Workspace.Bricks:GetChildren())do
        if v.Name == plrName then
            local pPos = v.Position
            local lPos = script.Parent:FindFirstChild("HumanoidRootPart").Position
            local pAvg = (pPos.X + pPos.Y + pPos.Z)/3
            local lAvg = (lPos.X + lPos.Y + lPos.Z)/3
            local sAway = math.abs(pAvg - lAvg)
            v:WaitForChild("NumVal").Value = sAway
        end
    end
    n = 0
    for i, v in pairs(game.Workspace.Bricks:GetChildren())do
        if v.Name == plrName then
            if n ~= 0 then
                if v:WaitForChild("NumVal").Value > n and v:WaitForChild("NumVal").Value < 10 then
                    rK.Enabled = true
                    rK.Adornee = v
                    n.Value = (v:WaitForChild("NumVal").Value)
                end
            else
                n = (v:WaitForChild("NumVal").Value)
            end
        end
    end
    wait(0.25)
end

but it says "attempt to index global 'n' (a number value)" Also, the person who spawned the part can only see the gui on that part.

Any help?