mysqmail-postfix-logger: command not found

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 Debian possible default full paths are:

/usr/sbin/mysqmail-postfix-logger - from package: mysqmail-postfix-logger

You may install the required package with command apt-get install {package}

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