I kept getting that message. This is the reply I received from Apple....
1) Make sure you're using the latest version of iTunes.
2) Open iTunes and sign in to the iTunes Store, if necessary.
3) Choose Check for Purchases from the Advanced menu. Enter your account name and password, then click Check. The missing item should begin downloading and appear in your Purchased playlist.
If you receive an error message while downloading, try again after turning off any firewall or web-accelerator software that you may have installed.
If the download process is interrupted for any reason, it should resume once you reopen iTunes.
This article provides information about resuming interrupted downloads:
http://www.info.apple.com/kbnum/n93015
If you don't see the item even when you select Library in the Source list, please reply to this email and include this information:
- The name of your Internet service provider (ISP)
- The type of Internet connection (such as dial-up, cable modem, or DSL)
- Any troubleshooting steps you may have taken
- Any error messages you may have received
Hope that helps! I used the support page to contact them. I emailed on Tuesday and they replied yesterday (thursday).