scope correction

function networkListener( event )
    if ( event.isError ) then
            print ( "Network error - download failed" )
    elseif ( event.phase == "ended" ) then
        groupHome:insert(event.target)
    end
end

local groupHome = display.newGroup()

local zimg_home_ad = display.loadRemoteImage( "IMG URL", "GET", networkListener, "zimg_home_ad.jpg", system.TemporaryDirectory, 0, 61 )