I have 16 students using the vex wireless programming kits to download their programs to their robots. However after almost every download, the system disconnects, they have to shut everything off, unplug the usb and then turn everything back on and then reconnect the usb before they can download a new file. This was supposed to make things easier? I have even had to download the master code to both the cortex and the joystick because it freeks out and messes up the master code somehow. Any idea how to fix this? It is doing it to all 16 kits.