Problems updating ipod
Make sure your device has enough free space to install an app update As our apps take up about 200MB to 600MB of space, it is best to keep about 500MB to 1GB of free space available on your device to install an app update.
After it's been restored, then you can update the operating system.
If you need to do this, sync your i Pod with i Tunes first to create a back up of all your data.
This is the Apple ID that was used to purchase the app.
Alternately, you can check your i Tunes purchase history to see if the account you are using was used to purchase an app.
But any time it does release an i Pod software update, you should install it.