Even though this is content that has played before, normally, by way of experiment try restarting iTunes in 32-bit mode and seeing if the content will play for you then. For instructions see the following document:
If the content does start playing properly then, restart iTunes in default (64-bit) mode again. Are the items working normally now?
I solved my problem!
I started-up off of my back up hard drive, downloaded the Mac OS X 10.7.5 Combi system update, and used it to reinstall the system update onto the primary hard drive. (I suppose you could run it from the primary hard drive if necessary.)
Other remedies that did NOT work:
- run DiskWarrior to rebuild directory
- startup from backup hard drive and reinstall iTunes 10.7 update