ssh-cron: 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/ssh-cron - from package: ssh-cron

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

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