Check your databases connection settings and also check that you have renamed the configuration files to .inc.php, not .inc.php.dist
Make sure your php installation has mysql support enabled and check your database setting in db.inc.phpAlso, check to make sure that your db.inc.php file is readable by the web server process. Some documentation recommends chmod 600 db.inc.php but a chmod 644 db.inc.php under a differently configured system will be just as secure and will alleviate this error message.
From the FAQ:QuoteMake sure your php installation has mysql support enabled and check your database setting in db.inc.phpAlso, check to make sure that your db.inc.php file is readable by the web server process. Some documentation recommends chmod 600 db.inc.php but a chmod 644 db.inc.php under a differently configured system will be just as secure and will alleviate this error message.
If it's not, don't forget to chmod 777 your /logs/ and /temp/ folders in your RoundCube folder.
When I have time, I'll write one, but at the moment, I don't. Sorry.