This message means that the database server software used to store the Q++Studio data (scripts, templates, holidays, ...) is not running.
To address this issue:
1. Make sure that Windows has been logged-on on the server PC (the server PC waiting for logon is the most common cause of this message).
2. Wait until Windows on the server is fully logged-on (about 3-5 minutes), and try again to launch Q++Studio from a workstation.
3. If the above does not get rid of the message, you can start the Q++Server software manually.