problem on peripheral.call reboot

local tArgs = { ... }
local uY, tX, tY, tZ = 1, tArgs[1], tArgs[2], tArgs[3]

function goToSky()
  while turtle.up() do
	uY = uY + 1
  end
  tY = tY + uY
  placeComputer()
end

function placeComputer()
  turtle.select(1) -- select the computer
  turtle.place()
  turtle.back()
  turtle.select(2) -- select wireless modem
  turtle.place()
  turtle.down()
  turtle.forward()
  turtle.select(4) -- select disk drive
  turtle.place()
  turtle.select(3) -- select floppy disk
  turtle.drop()
  setComputer()
end

function setComputer()
  turtle.down()
  turtle.forward()
  turtle.forward()
  turtle.turnLeft()
  turtle.turnLeft()
  turtle.up()
  setUpDisk(tX,tY,tZ)
  turtle.up()
  peripheral.call("front", "turnOn")
  turtle.down()
  turtle.suck() --take out floppy disk
  turtle.dig() -- take back disk drive
  turtle.up()
  peripheral.call("front", "reboot")
end

function setUpDisk(x,y,z)
-- DISK is set so it sets the computer startup
  local st = fs.open("disk/startup", "w")
  local gps_run = "shell.run('gps','host',"..x..","..y..","..z..")"
  st.writeLine("local startup = fs.open('startup', 'w')")
  st.writeLine("startup.writeLine(\""..gps_run.."\")")
  st.writeLine("startup.close()")
  st.close()
end

goToSky()