Elgg couldn't select the database 'c0_elgg', please check that the database is created and you have access to it. I got this, i chek the data, and i tried to change c0_elgg to c0elgg how it say in my ispconfig but still the same messinger Elgg couldn't select the database 'c0_elgg', please check that the database is created and you have access to it.
And you are able to login with phpmyadmin with the database user and password that you created for this database?