There is an error in the file “wp-security-core.php”
Change this line
load_textdomain( 'all-in-one-wp-security-and-firewall', WP_LANG_DIR . "/all-in-one-wp-security-and-firewall-$locale.mo" );
with:
load_textdomain( 'all-in-one-wp-security-and-firewall', WP_LANG_DIR . "/aiowpsecurity-$locale.mo" );
I hope developers will correct this error in the next update.
Bye