Hello,
Try these steps for your "Can't mount iPod" issue:
Eject your iPod from computer (for now).
Close Updater and iTunes programs.
Restart the computer.
Put your iPod into disk mode.
Connect your iPod to your computer.
See if your Updater works for your iPod.
Also, sometimes, when the Updater says "Can't mount iPod" it means that the iPod's actual hard drive is somehow out of place. Try this:
Tap your iPod firmly several times on both sides using your hand. This may work for you to tap your iPod's hard drive back to correct place. And it works for a lot of people! (if their iPod HD is out of place)
~~Kylene