Hello jwight,
It sounds like you are unable to download your purchased content, but you can find it without issue in the iTunes Store. I recommend signing out of your iTunes account with the following article:
iTunes 11 for Mac: Manage your iTunes Store account
http://support.apple.com/kb/PH12299
Then restart your computer, sign back in and try to download the purchase again.
If the issue persists, I would report an issue to the iTunes Support team with the following article:
How to report an issue with your iTunes Store, App Store, Mac App Store, or iBooks Store purchase
http://support.apple.com/kb/ht1933
Thank you for using Apple Support Communities.
All the best,
Sterling