My reply from apple
Dear Mark,
Thank you for contacting iTunes Store Customer Support. My name is Derrick. I understand that you this message comes up "pings failureType5002 customerMessageAn unknown error has occurred set-prefs preferred-audio-format256". Being a customer myself I can certainly understand your concern for this matter and I will be happy to assist you.
Mark, as an Advisor for the iTunes Store, I handle issues related to billing, downloading, customer accounts, and the items available on the iTunes Store. Although your question falls outside of my area of specialty, I will be happy to assist you with resolving your issue.
Listed below are some helpful tips and links. Once you have found a category that relates to your issue, follow the instructions or click on the associated link to go to that page.
A wide variety of helpful tutorials, troubleshooting steps, and support information can be found on the iTunes support website:
And another reply
I understand from your email request that you are receiving error 5002 when attempting to download your purchases. My name is Gerri, from your iTunes Store Customer Support Team. I can appreciate your desire to have this addressed as soon as possible so that you can download your songs to your account and I'll be happy to assist you today.
Many of my customers have resolved this issue by temporarily removing their credit card information from their account. Here are the steps:
1) Visit the Apple Store online:
http://store.apple.com/uk
2) Click Account in the upper-right corner, then click "Change account information" and sign in using the same Apple ID and password you use for the iTunes Store.
3) You should see your account-profile page. Under Method of Payment, remove all of the characters from the Card Number field. Do not change the expiration date or credit card type.
4) If you haven't already, select where you primarily use your purchases from the pop-up menu near the bottom of the page.
5) Click Continue. If you are asked to enter any other information, be sure to click Continue after making the updates so that your changes will be saved.
6) Make sure you're using the latest version of iTunes. It can be downloaded free of charge:
http://www.itunes.com/download
Note: Installing the latest version of iTunes will not affect your library or any items in your account that you haven't downloaded.
7) Click this link to open iTunes and access the Apple Account Information page:
http://phobos.apple.com/accountSummary
8) Sign in to the iTunes Store using your account name and password.
9) On the Apple Account Information page, click the Edit Payment Information button.
10) Enter your payment information and click Done to save your changes.
To ensure your account is functioning, try downloading a free item from the iTunes Store. To do this, navigate to the iTunes Store main page by clicking the Home icon near the upper-left corner of the window. Scroll down and click the "FREE ON iTunes" link near the bottom of the main page, then select an item to download.
I hope the above information has been helpful. If you have any additional questions or concerns regarding this issue or any other problems with any of your iTunes purchases, please be assured that I will be more than happy to try to assist you further.
Have a good day.
Sincerely,
Ms Gerri
iTunes Store/Mac App Store Customer Support