Microsoft Bookshelf: Please Insert The CD Message

I got the Microsoft Bookshelf application with the Library Research Software Bundle from Apple. Why do I get an error message asking me to insert the Microsoft Bookshelf CD-ROM disc when it is in the drive already?
The Microsoft Bookshelf CD is included with the following software bundles from Apple:

Library Research Bundle
Multimedia Learning Tools Bundle

Some early versions of the CD were improperly mastered which is the reason for the error message.

Please call 800-SOS-APPL to get the newer version of this CD.
Published Date: Feb 18, 2012