I purchased some music from iTunes some time ago but recently made a new Apple account when I bought an iPod Touch 4Gen. Now the music purchased on the old account will not play on the iPod set up with the new account. Any idea why? Is this because of some type of permissions issue?
Yes. The music is assigned to the old account. In order to play that music you will have to sign into your iPod with your old accounts credentials. There may be a way to merge accounts but I am unaware of that. Apple does this to ensure everyone on different accounts actually has to purchase music separately hence more profit for Apple.