I think the site has changed slightly, if you change
if (%tube.line == 5) {
to
if (%tube.line == 7) {
and change
if (%tube.line == 4) { inc %tube.line }
if (%tube.line == 3) { inc %tube.line }
if (%tube.line == 2) { inc %tube.line }
if (%tube.line == 1) { inc %tube.line }
to
if (%tube.line < 7) { inc %tube.line }
it works perfectly