For security reasons, it's often a good idea to have:
[mysqld]
local-infile=0
If you want to set all users except da_admin and root to not have that privilege at the mysql level, then login to mysql with the login/pass from /usr/local/directadmin/conf/mysql.conf, and run the query:
use mysql;
UPDATE mysql.user SET File_priv='N' WHERE user!='da_admin' AND user!='root';
FLUSH PRIVILEGES;
quit