Message: The RealBookKey could not be found.

This article applies to the previous 4.01 version and older.

Please update to the current version, which is the new minimum requirement for activation and support

Open a ticket here at the helpdesk to find out how.

The program isn't supposed to find the key. It has no idea where the email attachment has been downloaded to.
You have to direct the program to the file's location
Use the window that pops up to navigate (browse) to the RealBookKey.rbr file attachment from the e-mail.

You might find it in the e-mail itself and drag it to the desktop, in your e-mail program's attachment folder, or wherever you saved it when downloading it from your web e-mail.