nag-create-missing-add-histories-sql: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/nag-create-missing-add-histories-sql - from package: php-horde-nag

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/nag-create-missing-add-histories-sql - from package: php-horde-nag

You may install the required package with command apt-get install {package}
Error in other languages:
nag-create-missing-add-histories-sql: bevel nie gevind nie
nag-create-missing-add-histories-sql: comandă negăsită
nag-create-missing-add-histories-sql: comando não encontrado
nag-create-missing-add-histories-sql: commande introuvable
nag-create-missing-add-histories-sql: command not found
nag-create-missing-add-histories-sql: käsku ei ole
nag-create-missing-add-histories-sql: không tìm thấy lệnh
nag-create-missing-add-histories-sql: komanda nerasta
nag-create-missing-add-histories-sql: Kommando nicht gefunden.
nag-create-missing-add-histories-sql: kommandot finns inte
nag-create-missing-add-histories-sql: komut yok
nag-create-missing-add-histories-sql: nie znaleziono polecenia
nag-create-missing-add-histories-sql: níor aimsíodh an t-ordú
nag-create-missing-add-histories-sql: no se encontró la orden
nag-create-missing-add-histories-sql: no s'ha trobat l'ordre
nag-create-missing-add-histories-sql: opdracht niet gevonden
nag-create-missing-add-histories-sql: parancs nem található
nag-create-missing-add-histories-sql: perintah tidak ditemukan
nag-create-missing-add-histories-sql: príkaz nenájdený
nag-create-missing-add-histories-sql: příkaz nenalezen
nag-create-missing-add-histories-sql: команда не найдена
nag-create-missing-add-histories-sql: командата не е открита
nag-create-missing-add-histories-sql: 命令找不到
nag-create-missing-add-histories-sql: コマンドが見つかりません