There can be several reasons for this message:
* You don't have a database system installed.
* The database system is installed, but it's not running.
* You didn't select the correct database type when you tried to install your software
* The database hostname/DSN is incorrect.
* The database name you provided refers to a non-existing database.
* Your username to access the database is incorrect or this database user has insufficient privileges.
* Your password to access the database is incorrect.
Read the pre-installation section fo your softwre again. Be sure to complete the checklist at the end with the correct data.