What iOS was on the iPod?
Just what are you doing when it asks for PW to the old ID/email address?
Maybe this:
Find My iPhone Activation Lock
Try recovering use of the old account
if you forget your Apple ID password.
It's important to keep your Apple ID information up to date. If you no longer have access to the email address you currently use for your Apple ID, simply change it to your current, working email address. This will allow you to continue using your account and will ensure you can receive important account-related emails, reset your password, and more.
You can change your Apple ID to any other email address you control, as long as it's not already in use as an Apple ID.