Content Corrupt or Locked

I have the software for my Kobo Touch loaded on my Windows 7 PC.
When I attempt to open some of my books I get a message that says:

CONTENT LOCKED
We are unable to display the selected content. It may be locked or corrupt.
GO BACK TO LIBRARY

Any idea how to correct this? I have no clue how it could be locked as i just finished the book with no problems. I tried to reopen it on my device and it is locked up there too.

Any help would be greatly appreciated!