Delete the latest backup in iTunes/Edit/Preferences/Devices.
Make sure your secuirty software settings are correct:
Connect in recovery mode to make iTunes recognize again:
Follow the tips mentioned in this article:
Sorry it's took me a while to reply been ill.
I have done all of the above yet still this ipod will not update BUT now the back up will not back-up either,
saying there is an error with backing up,
my back up is not in the edit/preferences/devices bit either it will just not work.
Syncing will not work properley now too just keeps going in a loop trying to sync over and over and over, i really dont want to have to restore it without my back up as i will lose all my games i have paid for.
Sorry for being a pain but any other ideas ?
Apps can be downloaded again for free, Downloading past purchases from the App Store, iBookstore, and iTunes Store, the only thing you'll lose are the app settings.
A restore seems to be the only option to get your device working again. How to set up your iPhone or iPod touch as a new device