mcron: 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/bin/mcron - from package: mcron

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

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