Screen resolution problem

Hi,
i want to display screen border in every devices, but in some devices it doesen’t work, the lines are shifted more to right…

[lua]

local left= display.newLine(0,0,0,display.contentHeight)

left.strokeWidth= 2

local right = display.newLine(display.contentWidth,0,display.contentWidth,display.contentHeight)

right.strokeWidth=  2

local up = display.newLine(0,0,display.contentWidth,0)

up.strokeWidth=2

local down = display.newLine(0,display.contentHeight,display.contentWidth,display.contentHeight)

down.strokeWidth=2

[/lua]

and this is my config.lua that i find in internet…

[lua]

local w, h = display.pixelWidth, display.pixelHeight

local modes = {1, 1.5, 2, 3, 4, 6, 8} – Scaling factors to try  

local contentW, contentH = 480, 800   – Minimal size your content can fit in

– Try each mode and find the best one

local _w, _h, _m = w, h, 1  

for i = 1, #modes do  

    local m = modes[i]

    local lw, lh = w / m, h / m

    if lw < contentW or lh < contentH then

        break

    else

        _w, _h, _m = lw, lh, m

    end

end  

– If scaling is not pixel perfect (between 1 and 2) - use letterbox

if _m < 2 then  

    local scale = math.max(contentW / w, contentH / h)

    _w, _h = w * scale, h * scale

end

application = {  

    content = {

        width = _w,

        height = _h,

        scale = ‘letterbox’,

        fps = 60,

        imageSuffix = {

            [’@2x’] = 1.1,

            [’@4x’] = 2.1

        }

    }

}

[/lua]

I want to use 480x800, scaled in every devices, with the lines as screen border…sorry bad english