ener.hlp (Topic list)
Device unavailable (ERR: 68)
■ You have attempted to open a file that is not online or does
  not exist on your system.
 
■ Possible solutions:
 
  • Verify the device is connected to your computer.
 
  • Verify the device's power is on.
 
  • Change the specified device name to a valid name.
 
■ If you need additional help, move the cursor to a keyword
  and press F1 to open the Help window.