Have you actually extracted the exercises from the zip archive? or are you attempting to use them inside it?
In my experience, this is the behaviour you get when the databases are on locked media like a CD or DVD or where you have not logged on to them with a Full Access password.
You didn't open them as guest... where you shoul rather open them as as Admin (no password)
You need to copy them to your desktop and reopen them.
All will be reveiled then