Make sure the database is running.
If it is not running, MySQL can be started with the following command
service mysqld start
But it should be running as a daemon.
Make sure the database and user is created and that the user has the needed authorization.
On MySQL you'll have to do something like
mysql -u root -p
create database interformDatabase;
create user 'interformUser'@'localhost' identified by 'interformPassword';
grant alter, create, delete, drop, index, insert, select, update on interformDatabase.* to 'interformUser'@'localhost';
InterFormNG don't need all the granted privileges.
Alter, drop, etc. is only needed, if you want InterFormNG to create the needed table(s) and fields.
InterFormNG only needs insert, select and update priviledge.
Insert is only needed, if you use the metadata-table.
On a running production server it might be a good idea to only grant insert, select and update.