qmtpfront-echo: 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/qmtpfront-echo - from package: mailfront

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

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