I just reformatted my PC and installed Windows 7 today (legal version from TechNet).
I made sure before doing so that all my Zune content was backed up.
After re-installing the Zune software and copying all of my music content back to my PC, I got the error message: CAN’T PLAY
This item is no longer available at Zune Marketplace. Because of this, you can no longer play it or sync it with your Zune.
There might be another iteration of it available in Zune Marketplace.
Here is a picture to better describe my problem...