Touch Database Disk Image Malformed

Hello:

For some reason I received the error "Database Disk Image Malformed" this afternoon. I see that I have a number of backup files but I can find no way of restoring any of them. Will this process fix the problem? Will someone please explain how to do this?

Or, if this won't help, how do I tell the Kobo that I want to empty its library and allow me to send the books to it again?

Thanks in advance for all of your help.

Sparky